fix: Raise meaningful exception when oauth callback times out

[mafrosis]

I found that when timeout_seconds parameter is used, the code raises an exception such as:

  File "/usr/lib/python3.12/site-packages/google_auth_oauthlib/flow.py", line 520, in run_local_server
    authorization_response = wsgi_app.last_request_uri.replace("http", "https")
                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'replace'

This PR adds a custom exception such that a caller can handle this case.

I'm unable to run the full nox suite locally, but it looks like nothing has broken. I'll make any changes needed when the CI tests run.

[chalmerlowe]

Note to Reviewer:

Why did we subclass on 'AttributeError'?

'AttributeError' was historically the error that was raised if this line failed:

authorization_response = wsgi_app.last_request_uri.replace("http", "https")

and thus we want to minimize the possibility for a breaking change if customers have code such as the following present in their apps.

try:
    data = server_obj.attribute
except AttributeError:
    # Handle the missing value gracefully
    data = DEFAULT_VALUE

Because of Python’s exception hierarchy, any code catching AttributeError will also catch WSGITimeoutError.

[chalmerlowe]

LGTM