What and why?

I noticed a bug in Session Replay when the root wireframe (first wireframe in the list) is added in an incremental snapshot.

This wireframe will have no previousId, and the replay will add it last in the list of wireframes.

This should not happen very often, given we create a full snapshot on every RUM view.

Possible improvements for the PR:

• if the new root is already present in the previous wireframe, there is no need to create a new full snapshot

Also it's worth investigating why we're removing root wireframes in the first place (and thus adding them back afterwards).

Review checklist

• Feature or bugfix MUST have appropriate tests (unit, integration)
• Make sure each commit and the PR mention the Issue number or JIRA reference
• Add CHANGELOG entry for user facing changes

Custom CI job configuration (optional)

• Run unit tests for Core, RUM, Trace, Logs, CR and WVT
• Run unit tests for Session Replay
• Run integration tests
• Run smoke tests
• Run tests for tools/