Move the form signals from WebKitWebPage to WebKitWebFormManager that no longer uses WebKitDOMElement, but JSCValue.
Pull request: https://github.com/WebKit/WebKit/pull/7070
Committed 257366@main (81f661ea4d75): <https://commits.webkit.org/257366@main> Reviewed commits have been landed. Closing PR #7070 and removing active labels.