Edge: not properly loaded browser functions

[HeikoKlare]

There are issues with loading BrowserFunctions in Edge:

• Edge browser engine does not properly load BrowserFunction eclipse-platform/eclipse.platform.swt#2449
• Probably same as: [Edge][BrowserFunction] BrowserFunctions added to window undefined when URL loaded eclipse-platform/eclipse.platform.swt#20
• See also: BrowserFunction doesn't seem to be registered intermittently from Windows11/Edge/Webview2 on v4.31 eclipse-platform/eclipse.platform.swt#1274

The initialization logic should be improved such that the reported issues do not occur anymore. In particular:

• the snippet provided in the first issue should work
• the reported RichTextEditor scenario in 4diac should work (maybe reach out to Alois for testing potential fix)

Hint: there is a proposal how to fix the behavior for Edge: eclipse-platform/eclipse.platform.swt#20 (comment)