Element::userAgentShadowRoot() shouldn't return a RefPtr. It causes unnecessary ref-counting churn for caller that don't need it. Have it return a raw pointer instead and add a `protectedUserAgentShadowRoot()` getter for the callers that actually want a RefPtr.
Pull request: https://github.com/WebKit/WebKit/pull/24382
Committed 274602@main (9951fe460428): <https://commits.webkit.org/274602@main> Reviewed commits have been landed. Closing PR #24382 and removing active labels.
<rdar://problem/122927497>