fix artifacts diff

[ajtmccarty]

IFC-1020
no changelog b/c this new artifact query was introduced after 1.0 and never ported back, so we only need this update in 1.1

fixes a bug in the new query for getting artifact diffs. the bug was that the query only looked for CoreArtifacts created on the source_branch, but the CoreArtifact could have been created on the target_branch (always main for now) and then updated on the source_branch. I thought this kind of handling would not be necessary because CoreArtifacts are branch=local, but I did not consider the following case for branch=local schema

1. an artifact is created on main
2. we create a new branch branch2
3. the artifact generation logic makes an update to the existing artifact on branch2
   in this case, the CoreArtifact node is on the main branch, but it has updates to its attributes/relationships on the branch2 branch

added some unit tests and integration tests to cover this

[codspeed-hq]

CodSpeed Performance Report

Merging #5311 will not alter performance

_{Comparing ajtm-12232024-artifacts-diff (a87c35a) with release-1.1 (9b2562d)}

Summary

✅ 10 untouched benchmarks