Fix deep link gate being skipped when Aurora is already running

DeepLinkConfirmActivity shared the default task affinity with the main
Aurora task, so when the app was already running the system brought the
existing task to the foreground instead of launching the gate. Giving
the trampoline an empty task affinity decouples it from the main task,
so the confirmation sheet and target listing load every time.

app/src/main/AndroidManifest.xml

@@ -111,6 +111,7 @@
             android:excludeFromRecents="true"
             android:exported="true"
             android:launchMode="singleTop"
+            android:taskAffinity=""
             android:theme="@style/AppTheme.Translucent.Transparent">
             <intent-filter>
                 <action android:name="android.intent.action.VIEW" />