Avoid re-launching Keyguard warning dialog multiple times on orientation change.

Bug: 5211608
Change-Id: I13eb71fac954710bef8288294e96f9f60030ff6a
diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index 20df0d6..fd6933e 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -637,6 +637,7 @@
 
         <activity android:name="CredentialStorage"
                 android:theme="@style/Transparent"
+                android:launchMode="singleTop"
                 android:configChanges="orientation|keyboardHidden|screenSize">
             <intent-filter>
                 <action android:name="com.android.credentials.UNLOCK" />