[fenix] Suppress deprecation warnings for now-deprecated Glean APIs

Glean v39 allows to specify types for event extra keys.
The old API is therefore deprecated.
To avoid to much churn right now and keep the build going let's suppress
the deprecation warnings.

app/src/main/java/org/mozilla/fenix/components/metrics/GleanMetricsService.kt

@@ -99,10 +99,14 @@ private class EventWrapper<T : Enum<T>>(
             null
         }
 
+        @Suppress("DEPRECATION")
+        // FIXME(#19967): Migrate to non-deprecated API.
         this.recorder(extras)
     }
 }
 
+@Suppress("DEPRECATION")
+// FIXME(#19967): Migrate to non-deprecated API.
 private val Event.wrapper: EventWrapper<*>?
     get() = when (this) {
         is Event.OpenedApp -> EventWrapper(

app/src/main/java/org/mozilla/fenix/telemetry/TelemetryLifecycleObserver.kt

@@ -35,6 +35,8 @@ class TelemetryLifecycleObserver(
         val lastState = pausedState ?: return
         val currentState = createTabState()
 
+        @Suppress("DEPRECATION")
+        // FIXME(#19967): Migrate to non-deprecated API.
         EngineMetrics.foregroundMetrics.record(mapOf(
             MetricsKeys.backgroundActiveTabs to lastState.activeEngineTabs.toString(),
             MetricsKeys.backgroundCrashedTabs to lastState.crashedTabs.toString(),