fix(sdk)!: don't allow duplicate mock expectations

[lklimek]

Issue being fixed or feature implemented

Right now, when adding new expected request/response pair to rs-sdk / rs-dapi-client with the duplicate request, previous request is silently replaced. This can cause non-deterministic behavior, where test result depends on order in which expectations are added.

What was done?

Return error when duplicate expectation is created.

Separate test vectors from various tests into separate directories (namespaces) to avoid conflicts.

How Has This Been Tested?

Added unit tests.

Commented out code that deletes old test vectors. Then, called the following command 3 times, to generate conflicting test vectors:

./packages/rs-sdk/scripts/generate_test_vectors.sh document_read

Then started cargo test -p rs-sdk document_read to ensure it fails with MockExpectationConflict errors.

Breaking Changes

• Adding duplicate mock expectation returns error
• Changed structure of test vectors directory

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated relevant unit/integration/functional/e2e tests
• I have added "!" to the title and described breaking changes in the corresponding section if my code contains any
• I have made corresponding changes to the documentation if needed

For repository code-owners and collaborators only

• I have assigned this pull request to a milestone