Remove extension telemetry setting and use VS Code setting instead

[koesie10]

This removes the codeQL.telemetry.enableTelemetry setting and uses the VS Code settings instead. This is done automatically in the vscode-extension-telemetry package, so we don't need to check the VS Code settings.

Since this changes the telemetry when you currently have the extension telemetry disabled, but the VS Code telemetry enabled, this also adds a non-dismissable notification when starting the extension (if VS Code telemetry is enabled and codeQL.telemetry.enableTelemetry is false).

The E2E tests are expected to fail since it installs the released extension rather than the extension from the repo.

• Closes Less obtrusive way to ask users to collect telemetry #3672

[robertbrignull]

Code LGTM and I tried it out and the popup worked as expected (one non-blocking comment)

[robertbrignull]

It's slightly annoying you get a "cancel" button but if you click it the dialog just comes back. Sadly I can't see a way to get rid of it and there's nothing sensible we can really do to "cancel" this update, so I agree I think we just leave it like this. Users will only see it once at least.

[koesie10]

Yes, I agree that this is quite annoying, but I also couldn't find a way to hide it. An alternative solution would be to keep the old setting for a few releases while showing this dialog, where the cancel button would simply keep using the old setting. However, we hope this scenario is quite rare and don't think it's worth the effort to have a "transition" like that which would require some additional work in a few releases.