fix: update crossOrigin description to clarify requirement when using as="fetch"

[vishal-rathod-07]

Update crossOrigin prop description to explicitly state that it's required when using as="fetch".

The documentation lacked clarity in several places about the mandatory nature of crossOrigin when the as prop is set to "fetch". This change:

• Adds explicit requirement note in prop descriptions
• Ensures consistent documentation across all relevant files
• Helps developers avoid common misconfiguration issues

Also closes #6617

[sophiebits]

as="fetch" isn't valid for these so this doesn't make sense. If you want to preload a URL that you will fetch then I believe call preload with as="fetch".

[sophiebits]

For preloadModule perhaps we could allow setting as to "audioworklet", "paintworklet", "serviceworker", "sharedworker", or "worker" per MDN https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/Attributes/rel/modulepreload, but still "fetch" wouldn't be supported.