ask once to share after the first drive that works, cache the cert for settings

gearslip/src/main/AndroidManifest.xml

@@ -160,6 +160,11 @@
             android:name=".notify.TestMessageReceiver"
             android:exported="false" />
 
+        <!-- The one-time "Gearslip worked with your car" ask: its Share and Not now buttons. -->
+        <receiver
+            android:name=".stats.WorkedPromptReceiver"
+            android:exported="false" />
+
         <service
             android:name=".mirror.MirrorService"
             android:exported="false"