feat: add LinearRegression.predict_explain() to generate ML.EXPLAIN_PREDICT columns

[arwas11]

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  • predict_Explain: screen/BmpXWdueDEz9K9P

Fixes #379743762 🦕

[tswast]

Doctest failed, but doesn't appear to be related:

FAILED third_party/bigframes_vendored/pandas/core/frame.py::frame.DataFrame.update

_______________________ [doctest] frame.DataFrame.update _______________________
[gw1] linux -- Python 3.12.0 /tmpfs/src/github/python-bigquery-dataframes/.nox/doctest/bin/python
4066 
4067             >>> import bigframes.pandas as bpd
4068             >>> bpd.options.display.progress_bar = None
4069 
4070             >>> df = bpd.DataFrame({'A': [1, 2, 3],
4071             ...                    'B': [400, 500, 600]})
4072             >>> new_df = bpd.DataFrame({'B': [4, 5, 6],
4073             ...                        'C': [7, 8, 9]})
4074             >>> df.update(new_df)
4075             >>> df
UNEXPECTED EXCEPTION: BadRequest('GET [https://bigquery.googleapis.com/bigquery/v2/projects/bigframes-testing/queries/a0e298c3-d88a-43a3-8ee8-06454d818cbe?maxResults=0&location=US&prettyPrint=false](https://www.google.com/url?q=https://bigquery.googleapis.com/bigquery/v2/projects/bigframes-testing/queries/a0e298c3-d88a-43a3-8ee8-06454d818cbe?maxResults%3D0%26location%3DUS%26prettyPrint%3Dfalse&sa=D): The job encountered an internal error during execution and was unable to complete successfully.')