Use DestructionThread::Main for RTCRtpScriptTransform
<rdar://76404727>
<rdar://problem/76451107>
<rdar://problem/76404727>
Created attachment 425616 [details] Patch
Committed r275815 (236385@main): <https://commits.webkit.org/236385@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 425616 [details].