[Cocoa] In-band captions generate large, line-wrapped cues
<rdar://problem/119024855>
Pull request: https://github.com/WebKit/WebKit/pull/21148
Committed 271415@main (53b6a4522e45): <https://commits.webkit.org/271415@main> Reviewed commits have been landed. Closing PR #21148 and removing active labels.