[iOS] MediaSessionManager continues to monitor wireless targets when a page is no longer visible
<rdar://problem/107220858>
Pull request: https://github.com/WebKit/WebKit/pull/15716
Committed 265965@main (ecb0f69a544d): <https://commits.webkit.org/265965@main> Reviewed commits have been landed. Closing PR #15716 and removing active labels.