Enable management of WebKit process as extensions by default.
<rdar://problem/118035310>
Pull request: https://github.com/WebKit/WebKit/pull/20084
Committed 270410@main (0eb9ec0102d9): <https://commits.webkit.org/270410@main> Reviewed commits have been landed. Closing PR #20084 and removing active labels.
Re-opened since this is blocked by bug 264517
Pull request: https://github.com/WebKit/WebKit/pull/20348
Committed 270583@main (1f8870d0b897): <https://commits.webkit.org/270583@main> Reviewed commits have been landed. Closing PR #20348 and removing active labels.
Re-opened since this is blocked by bug 264758
Pull request: https://github.com/WebKit/WebKit/pull/20755