Fix triggerer file handle leak when remote log upload fails

[potiuk]

Summary

When a trigger finishes, TriggerRunnerSupervisor._handle_request()
uploads its log file to the remote store and then closes the local
file descriptor:

if factory := self.logger_cache.pop(id, None):
    factory.upload_to_remote()
    # Need to close the FD explicitly, as it is not closed when logger is removed.
    factory.close()

If factory.upload_to_remote() raises (e.g. S3/GCS throttling, transient
network errors), factory.close() is never called. The factory has
already been popped from logger_cache, so nothing else will close the
underlying BufferedWriter — its 8 KiB buffer plus the open fd leak for
every failed upload, and the exception escapes into handle_requests
where it is not handled.

Wrap the cleanup in try/except/finally so the fd is always closed and
the failure is logged instead of propagating.

Surfaced in #65985.

Test plan

• New unit test test_trigger_logger_fd_closed_when_upload_to_remote_raises
  mocks upload_to_remote() to raise and asserts close() still
  runs and logger_cache / running_triggers are cleaned up.
• Existing test_trigger_logger_close still passes.
• prek run clean on changed files (ruff, mypy-airflow-core, bandit, etc.).

---

Was generative AI tooling used to co-author this PR?

• Yes — Claude Opus 4.7 (1M context)

Generated-by: Claude Opus 4.7 (1M context) following the guidelines

[github-actions]

Backport successfully created: v3-2-test

Note: As of Merging PRs targeted for Airflow 3.X
the committer who merges the PR is responsible for backporting the PRs that are bug fixes (generally speaking) to the maintenance branches.

In matter of doubt please ask in #release-management Slack channel.

Status	Branch	Result
✅	v3-2-test