[Cocoa] Rename FontCustomPlatformDataMac to FontCustomPlatformDataCoreText
<rdar://problem/108924213>
Pull request: https://github.com/WebKit/WebKit/pull/13472
Committed 263706@main (237442dfbbc2): <https://commits.webkit.org/263706@main> Reviewed commits have been landed. Closing PR #13472 and removing active labels.