Name user call activity "Phone"

Name the main call activity differently from the app label so that
it's a simpler name in activity disambuation dialogues.

Bug:23090337
Change-Id: I2f4eb92022dcce2c29f08dc4cdd2ee4282af8842
diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index ac3799f..f4ae711 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -88,6 +88,7 @@
              URL with the schemes "tel", "sip", and "voicemail". It also handles URLs linked to
              contacts provider entries. Any data not fitting the schema described is ignored. -->
         <activity android:name=".components.UserCallActivity"
+                android:label="@string/userCallActivityLabel"
                 android:theme="@style/Theme.Telecomm.Transparent"
                 android:permission="android.permission.CALL_PHONE"
                 android:excludeFromRecents="true"