Fix newly installed providers bug

Package monitor was not registered
properly.

Change-Id: Ifde2e6027b2aee2355114c8ff9b0d1f542fa2f8d
Test: treehugger
Bug: 280867431

src/com/android/settings/applications/credentials/CredentialManagerPreferenceController.java

@@ -120,6 +120,7 @@ public class CredentialManagerPreferenceController extends BasePreferenceControl
         mCredentialManager =
                 getCredentialManager(context, preferenceKey.equals("credentials_test"));
         new SettingContentObserver(mHandler).register(context.getContentResolver());
+        mSettingsPackageMonitor.register(context, context.getMainLooper(), false);
     }
 
     private @Nullable CredentialManager getCredentialManager(Context context, boolean isTest) {