…loud Run mis-configuration (#1880)

This patch adds a fallback logic to look for Cloud Run cert/keys in the
well-known location if the cert config contains the exact incorrect
cert/key paths AND the incorrect cert/key paths point to non-existent
files.

Note: This patch will be reverted sometime in Jan 2026, after Cloud Run
environment is updated with the correct cert configs. The revert will be
tracked by #1881

PR created by the Librarian CLI to initialize a release. Merging this PR
will auto trigger a release.

Librarian Version: v0.7.0
Language Image:
us-central1-docker.pkg.dev/cloud-sdk-librarian-prod/images-prod/python-librarian-generator:latest
<details><summary>google-auth: 2.44.0</summary>

##
[2.44.0](googleapis/google-auth-library-python@v2.43.0...v2.44.0)
(2025-12-12)

### Features

* MDS connections use mTLS (#1856)
([0387bb95](googleapis/google-auth-library-python@0387bb95))

* support Python 3.14 (#1822)
([0f7097e7](googleapis/google-auth-library-python@0f7097e7))

* add ecdsa p-384 support (#1872)
([39c381a5](googleapis/google-auth-library-python@39c381a5))

* Add shlex to correctly parse executable commands with spaces (#1855)
([cf6fc3cc](googleapis/google-auth-library-python@cf6fc3cc))

* Implement token revocation in STS client and add revoke() metho…
(#1849)
([d5638986](googleapis/google-auth-library-python@d5638986))

### Bug Fixes

* Add temporary patch to workload cert logic to accomodate Cloud Run
mis-configuration (#1880)
([78de7907](googleapis/google-auth-library-python@78de7907))

* Delegate workload cert and key default lookup to helper function
(#1877)
([b0993c7e](googleapis/google-auth-library-python@b0993c7e))

* Use public refresh method for source credentials in
ImpersonatedCredentials (#1884)
([e0c3296f](googleapis/google-auth-library-python@e0c3296f))

</details>

Co-authored-by: release-please[bot] <55107282+release-please[bot]@users.noreply.github.com>

Fixes internal issue 427501553