probe-scraper fog expiry crashes when encountering access-restricted bugs

[badboy]

The latest probe-scraper probe_scraper_check_fog_expiry check failed due to a bug referenced in the bugs list of an expiring metric being confidential and thus not accessible by our bot account.

[2024-09-05, 03:58:58 UTC] {pod_manager.py:466} INFO - [base] Error response: {"code":102,"error":true,"documentation":"https://bmo.readthedocs.io/en/latest/api/","message":"You are not authorized to access bug 1900840."}
[2024-09-05, 03:58:58 UTC] {pod_manager.py:466} INFO - [base] Needinfo request failed, retrying request without needinfo
[2024-09-05, 03:58:58 UTC] {pod_manager.py:466} INFO - [base] Failed to create bugs with arguments: {'product': 'Firefox', 'component': 'General', 'summary': 'Remove or update metrics expiring in Firefox 133: private_browsing.window_open_during_teardown', 'description': "\nThe following metrics will expire in the next Firefox Nightly release: [version 133][1].\n\n```\nprivate_browsing.window_open_during_teardown\n```\n\n\n\nWhat to do about this:\n1. If one, some, or all of the metrics are no longer needed, please remove them from their `metrics.yaml` definition file.\n2. If one, some, or all of the metrics are still required, please submit a patch to extend their expiry.\n\nIf you have any problems, please ask for help on the [#glean Matrix room](https://chat.mozilla.org/#/room/#glean:mozilla.org) or the #data-help Slack channel.\nWe'll give you a hand.\n\nYour Friendly Neighbourhood Glean Team\n\n[1]: https://wiki.mozilla.org/Release_Management/Calendar\n\n---\nThis bug was auto-filed by [probe-scraper](https://github.com/mozilla/probe-scraper).\n", 'version': 'unspecified', 'type': 'task', 'whiteboard': '[metric-expiry-alert]', 'see_also': [1900840], 'flags': []}
[2024-09-05, 03:58:58 UTC] {pod_manager.py:466} INFO - [base] Error response: {"code":102,"error":true,"documentation":"https://bmo.readthedocs.io/en/latest/api/","message":"You are not authorized to access bug 1900840."}

[2024-09-05, 03:58:58 UTC] {pod_manager.py:483} INFO - [base] requests.exceptions.HTTPError: 401 Client Error: Unauthorized for url: https://bugzilla.mozilla.org/rest/bug

(the bug number is publicly listed in the metrics.yaml, so it's fine posting here. The metric also has an actual public bug for the data review)

No bug is created.
probe-scraper fails.
I'm not sure if other expiring metrics would get a bug filed or if this hard-stops the process.

Nonetheless we should probably try to handle this more gracefully.