Migrate more events to telemetry::event! macro (#24102)

I believe this takes care of the remaining events running through the
old flow that requires transformation at the collab server level. I
think all events are now going through `telemetry::event!()`.

For anyone curious where the new telemetry names are coming from, you
can check the `for_snowflake` function within
`crates/collab/src/api/events.rs`, to see how collab is currently
transforming the events going through the old flow.

Release Notes:

- N/A

crates/extensions_ui/src/extensions_ui.rs

@@ -1207,7 +1207,7 @@ impl Item for ExtensionsPage {
     }
 
     fn telemetry_event_text(&self) -> Option<&'static str> {
-        Some("extensions page")
+        Some("Extensions Page Opened")
     }
 
     fn show_toolbar(&self) -> bool {