handle deprecation of pandas.Series.dt.to_pydatetime() calls and suppress their FutureWarnings

[ned2]

As of Pandas 2.1.0, it is deprecating the behaviour of Series.dt.to_pydatetime(), which currently returns a numpy.ndarray, and changing it to return a pandas.Series of Python datetime objects.

https://pandas.pydata.org/docs/reference/api/pandas.Series.dt.to_pydatetime.html

This PR fixes #4363. The issue is that user's consoles are currently spammed with a FutureWarning containing this warning, which they cannot do anything about as the warning is coming inside the Plotly Package.

The fix is to first wrap the output of Series.dt.to_pydatetime() with an np.array() call, so that the code will continue to work when the behaviour change drops. Then secondly, each offending call is put inside a warnings.catch_warnings() context manager that suppresses the FutureWarning only for the contents of the with block.

Code PR

• I have read through the contributing notes and understand the structure of the package. In particular, if my PR modifies code of plotly.graph_objects, my modifications concern the codegen files and not generated files.
• I have added tests (if submitting a new feature or correcting a bug) or
  modified existing tests.
• For a new feature, I have added documentation examples in an existing or
  new tutorial notebook (please see the doc checklist as well).
• I have added a CHANGELOG entry if fixing/changing/adding anything substantial.
• For a new feature or a change in behaviour, I have updated the relevant docstrings in the code to describe the feature or behaviour (please see the doc checklist as well).

[alexcjohnson]

💃 Looks great, thanks @ned2! Please add a changelog entry and we'll merge.

[ned2]

easy, changelog entry added @alexcjohnson