Fixes #2361

Description

Add a trigger on the campaign_contact table to update the "updated_at" column whenever changes are made to the table.

[ ] I have manually tested my changes on desktop and mobile N/A - change is a database migration
[X] The test suite passes locally with my changes
[X] If my change is a UI change, I have attached a screenshot to the description section of this pull request
[X] My change is 300 lines of code or less, or has a documented reason in the description why it’s longer
[X] I have made any necessary changes to the documentation
[ ] I have added tests that prove my fix is effective or that my feature works N/A - change is a database migration
[X] My PR is labeled [WIP] if it is in progress