Make code changes to address all test warnings

[grahamalama]

Ahh, a test suite run with no warnings reported

================================================================================================ test session starts ================================================================================================
platform darwin -- Python 3.12.4, pytest-8.3.2, pluggy-1.5.0
rootdir: /Users/gbeckley/code/github/mozilla-it/ctms-api
configfile: pyproject.toml
testpaths: tests/unit
plugins: Faker-26.0.0, anyio-4.4.0, factoryboy-2.7.0
collected 484 items                                                                                                                                                                                                 

tests/unit/bin/test_client_credentials.py ................                                                                                                                                                    [  3%]
tests/unit/routers/contacts/test_api.py ......................................................                                                                                                                [ 14%]
tests/unit/routers/contacts/test_api_delete.py ...                                                                                                                                                            [ 15%]
tests/unit/routers/contacts/test_api_get.py ......                                                                                                                                                            [ 16%]
tests/unit/routers/contacts/test_api_get_by_alt_id.py ...................                                                                                                                                     [ 20%]
tests/unit/routers/contacts/test_api_patch.py ............................................................................................................................                                    [ 45%]
tests/unit/routers/contacts/test_api_post.py ..................................................                                                                                                               [ 56%]
tests/unit/routers/contacts/test_api_put.py ...................................................                                                                                                               [ 66%]
tests/unit/routers/contacts/test_bulk.py .................                                                                                                                                                    [ 70%]
tests/unit/routers/contacts/test_private_api.py ..............................                                                                                                                                [ 76%]
tests/unit/routers/test_platform.py .........                                                                                                                                                                 [ 78%]
tests/unit/schemas/test_contact.py ......                                                                                                                                                                     [ 79%]
tests/unit/schemas/test_newsletter.py ..                                                                                                                                                                      [ 79%]
tests/unit/schemas/test_waitlist.py ..............................                                                                                                                                            [ 86%]
tests/unit/test_auth.py .................                                                                                                                                                                     [ 89%]
tests/unit/test_backport_legacy_waitlists.py ....                                                                                                                                                             [ 90%]
tests/unit/test_crud.py ...............................                                                                                                                                                       [ 96%]
tests/unit/test_log.py ......                                                                                                                                                                                 [ 98%]
tests/unit/test_metrics.py .........                                                                                                                                                                          [100%]

=============================================================================================== 484 passed in 54.01s ================================================================================================

[grahamalama]

Since merging #932, a warning is being triggered when we call init_metrics_labels 🤔

tests/unit/test_metrics.py::test_init_metrics_labels
  /Users/gbeckley/code/github/mozilla-it/ctms-api/.venv/lib/python3.12/site-packages/fastapi/openapi/utils.py:207: UserWarning: Duplicate Operation ID lbheartbeat___lbheartbeat___head for function lbheartbeat at /Users/gbeckley/code/github/mozilla-it/ctms-api/.venv/lib/python3.12/site-packages/dockerflow/fastapi/views.py
    warnings.warn(message, stacklevel=1)

tests/unit/test_metrics.py::test_init_metrics_labels
  /Users/gbeckley/code/github/mozilla-it/ctms-api/.venv/lib/python3.12/site-packages/fastapi/openapi/utils.py:207: UserWarning: Duplicate Operation ID heartbeat___heartbeat___head for function heartbeat at /Users/gbeckley/code/github/mozilla-it/ctms-api/.venv/lib/python3.12/site-packages/dockerflow/fastapi/views.py
    warnings.warn(message, stacklevel=1)

We might have to settle with 1 warning, for now

[alexcottner]

seems good