[components] Handle GeckoView EME permission requests.

This allows Fenix to play EME content without having to toggle manually
`media.eme.require-app-approval=false` in `about:config`.

Closes mozilla-mobile/android-components#7121

X-Channel-Revision: [main] mozilla-mobile/android-components@cf522a7
X-Channel-Revision: [main] mozilla-mobile/fenix@20b25d7
X-Channel-Revision: [main] mozilla-mobile/focus-android@29486b8
X-Channel-Converted-Revision: [ac-prep] mozilla-mobile/firefox-android@ac788e1

_meta/mozilla-mobile-firefox-android.json

@@ -1,6 +1,6 @@
 {
   "name": "mozilla-mobile/firefox-android",
   "revs": {
-    "ac-prep": "89348a0424609ba7efcaaf83ad15cecd83dc504a"
+    "ac-prep": "ac788e1caf34b2bae236d33221e53d9e9de77ce9"
   }
 }

mozilla-mobile/firefox-android/android-components/components/feature/sitepermissions/src/main/res/values/strings.xml

@@ -33,4 +33,6 @@
     <string name="mozac_feature_sitepermissions_never_allow">Never</string>
     <!-- Title of a dialog to require to save data in persistent storage. %1$s will be replaced with the URL of the current page -->
     <string name="mozac_feature_sitepermissions_persistent_storage_title">Allow %1$s to store data in persistent storage?</string>
+    <!-- Title of a dialog to use EME. %1$s will be replaced with the URL of the current page -->
+    <string name="mozac_feature_sitepermissions_media_key_system_access_title">Allow %1$s to play DRM-controlled content?</string>
 </resources>