Our internal CI system has revealed that some watchOS build environments meet the version check, but still lack the actual LockdownMode.framework and headers. To avoid breaking these configurations (and any other similar platform issues), add a __has_include check.
<rdar://problem/110530785>
Pull request: https://github.com/WebKit/WebKit/pull/14812
Committed 265025@main (e1b1a8e15911): <https://commits.webkit.org/265025@main> Reviewed commits have been landed. Closing PR #14812 and removing active labels.