Drop unnecessary lambda capturing in KeyframeEffectStack::ensureEffectsAreSorted().
<rdar://problem/105696810>
Pull request: https://github.com/WebKit/WebKit/pull/10399
Committed 260576@main (6d565d6ca8ab): <https://commits.webkit.org/260576@main> Reviewed commits have been landed. Closing PR #10399 and removing active labels.