BE story that supports update of conflict declarations by reviewers and TTA members

STT-885 was written in a way that described FE behavior while it was estimated for BE only. While I already had the conflict_declaration_update in place, there were a few tests that needed to be added to confirm the desired behavior outlined in this ticket. With these tests, I ended up refactoring the tests to use parameterization for those most common groups of tests.

Per Allie's recommendation, I created STT-1162 to define the acceptance criteria for the UI and connection work with the BE.