[fenix] Switch to the typed API for Glean events

Required for Glean v52.0.0

Ref https://github.com/mozilla-mobile/fenix/issues/19967

app/metrics.yaml

@@ -7555,26 +7555,33 @@ engine_tab:
         description: |
           Number of active tabs (with an engine session assigned) when the app
           went to the background.
+        type: string
       background_crashed_tabs:
         description: |
           Number of tabs marked as crashed when the app went to the background.
+        type: string
       background_total_tabs:
         description: |
           Number of total tabs when the app went to the background.
+        type: string
       foreground_active_tabs:
         description: |
           Number of active tabs (with an engine session assigned) when the
           app came back to the foreground.
+        type: string
       foreground_crashed_tabs:
         description: |
           Number of tabs marked as crashed when the app came back to the
           foreground.
+        type: string
       foreground_total_tabs:
         description: |
           Number of total tabs when the app came back to the foreground.
+        type: string
       time_in_background:
         description: |
           Time (in milliseconds) the app was in the background.
+        type: string
     metadata:
       tags:
         - Performance

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

@@ -10,7 +10,7 @@ import androidx.lifecycle.LifecycleOwner
 import mozilla.components.browser.state.store.BrowserStore
 import mozilla.components.support.base.android.Clock
 import org.mozilla.fenix.GleanMetrics.EngineTab as EngineMetrics
-import org.mozilla.fenix.GleanMetrics.EngineTab.foregroundMetricsKeys as MetricsKeys
+import org.mozilla.fenix.GleanMetrics.EngineTab.ForegroundMetricsExtra as MetricsExtra
 
 /**
  * [LifecycleObserver] to used on the process lifecycle to measure the amount of tabs getting killed
@@ -33,17 +33,15 @@ 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(),
-                MetricsKeys.backgroundTotalTabs to lastState.totalTabs.toString(),
-                MetricsKeys.foregroundActiveTabs to currentState.activeEngineTabs.toString(),
-                MetricsKeys.foregroundCrashedTabs to currentState.crashedTabs.toString(),
-                MetricsKeys.foregroundTotalTabs to currentState.totalTabs.toString(),
-                MetricsKeys.timeInBackground to (currentState.timestamp - lastState.timestamp).toString(),
+            MetricsExtra(
+                backgroundActiveTabs = lastState.activeEngineTabs.toString(),
+                backgroundCrashedTabs = lastState.crashedTabs.toString(),
+                backgroundTotalTabs = lastState.totalTabs.toString(),
+                foregroundActiveTabs = currentState.activeEngineTabs.toString(),
+                foregroundCrashedTabs = currentState.crashedTabs.toString(),
+                foregroundTotalTabs = currentState.totalTabs.toString(),
+                timeInBackground = (currentState.timestamp - lastState.timestamp).toString(),
             ),
         )