AVVideoCaptureSource::setupSession should fall back to `+[[AVCaptureSession alloc] init]` if `+[[AVCaptureSession alloc] initWithAssumedIdentity:identity:]` fails
<rdar://problem/96626753>
Pull request: https://github.com/WebKit/WebKit/pull/2198
Committed 252248@main (b9dc4e5eb87a): <https://commits.webkit.org/252248@main> Reviewed commits have been landed. Closing PR #2198 and removing active labels.