[visionOS] Create infrastructure for passing spatial tracking labels from the UIProcess to the GPU process
<rdar://problem/123067651>
<rdar://problem/123067618>
Pull request: https://github.com/WebKit/WebKit/pull/24586
Committed 274873@main (69d7153aa848): <https://commits.webkit.org/274873@main> Reviewed commits have been landed. Closing PR #24586 and removing active labels.