#2040 Search NotificationHistory for GA4

[kalbfled]

Description

When veterans open an e-mail notification, a GET request gets made that kicks off a Celery task that looks up a notification in the "notifications" table. However, the notification might have moved to the "notification_history" table. The changes search the latter table if the notification isn't found in the former table.

I also changed a logging statement from "error" to "warning". A veteran might open a message after the notification is purged from history, and that is not an error.

issue #2040

How Has This Been Tested?

I wrote a new unit test.

Checklist

• [x] I have assigned myself to this PR
• [x] PR has an appropriate title: #9999 - What the thing does
• [x] PR has a detailed description, including links to specific documentation
• [x] I have added the appropriate labels to the PR.
• [x] I did not remove any parts of the template, such as checkboxes even if they are not used
• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to any documentation
• [x] My changes generate no new warnings
• [x] I have added tests that prove my fix is effective or that my feature works. Testing guidelines
• [x] I have ensured the latest main is merged into my branch and all checks are green prior to review
• [x] New and existing unit tests pass locally with my changes
• [x] Any dependent changes have been merged and published in downstream modules
• [x] The ticket was moved into the DEV test column when I began testing this change