Like the Decoder counterparts, the WebCodecs encoders store refs to Strong callbacks which leak the Document.
<rdar://problem/131327288>
Pull request: https://github.com/WebKit/WebKit/pull/30574
Committed 280762@main (a0a1e48bd8e0): <https://commits.webkit.org/280762@main> Reviewed commits have been landed. Closing PR #30574 and removing active labels.