Revert mutation observer refactor
Created by: lguychard
Fixes #3166 (closed) (temp fix)
- Revert e673fe4: Handle all git change types in Bitbucket PRs (#3086)
- Revert 0d3294e: Change browser extension to use a single MutationObserver (#2909)
Created by: lguychard
Fixes #3166 (closed) (temp fix)