Bugzilla

Summary: Create a few broad widget telemetry events (that include a widget_name param), so we can launch multiple widgets without the need for bespoke telemetry updates for each.

Note: We want to send duplicate events until DS can confirm the new probes work as expected. 

Tasks:
- Define new entries in metrics.yaml
- Add new Glean event calls in existing code ([TelemetryFeed.sys.mjs example](https://searchfox.org/firefox-main/source/browser/extensions/newtab/lib/TelemetryFeed.sys.mjs#1699-1710)) 
- (Follow-up, [separate patch](https://bugzilla.mozilla.org/show_bug.cgi?id=2012779)) Remove previous events

~(Duplicated comment from the summary. Please ignore!)~