[MatrixRTC] Improve livekit object validation checks

[toger5]

Otherwise passing undefined throws.

Signed-off-by: Timo K [email protected]

Checklist

• [x] Tests written for new code (and old code if feasible).
• [x] New or updated public/exported symbols have accurate TSDoc documentation.
• [x] Linter and other CI checks pass.
• [x] Sign-off given on the changes (see CONTRIBUTING.md).

[richvdh]

Improve is livekit checks

this doesn't seem to make sense? Should this be "Improve isLivekit checks" or similar?

and first.

and first?

[Half-Shot]

(There was some feedback that the title could be better in the web chapter, so I tried to tidy it up)

[Half-Shot]

We discussed within the VoIP team and have parked this until we have more time to finish the PR.