Firefox/Safari don't support InstallEvent interface

[caugner]

Summary

Update Firefox/Safari statements for InstallEvent interface.

Test results and supporting details

Both "only" support the install event, but it is of type ExtendableEvent, not InstallEvent.

Related issues

Opened openwebdocs/mdn-bcd-collector#3020 to update the collector test.

Fixes #22591.

[github-actions]

Tip: Review these changes grouped by change (recommended for most PRs), or grouped by feature (for large PRs).

[ddbeck]

Both "only" support the install event, but it is of type ExtendableEvent, not InstallEvent.

This suggests to me that api.ServiceWorkerGlobalScope.install_event needs a note to indicate the type sent to an event listener is not the correct type. (It's probably not partial though, if this is the first we're noticing of it.)

[caugner]

This suggests to me that api.ServiceWorkerGlobalScope.install_event needs a note to indicate the type sent to an event listener is not the correct type. (It's probably not partial though, if this is the first we're noticing of it.)

Good point, added in ac825c3.

[ddbeck]

Approved, but with a comment to improve the text of the event notes.