[test] fix SystemUITests

Non-data apps that have a sharedUserId shared with a privileged app and
use privileged permissions need to testOnly.

BUG: 236173905
Fixes: 243736722
BUG: 243736722
Test: atest SystemUITests
Change-Id: I466b4c305fc0882e036298840c04601747882b18
diff --git a/packages/SystemUI/tests/AndroidTest.xml b/packages/SystemUI/tests/AndroidTest.xml
index 5ffd300..31e7bd2 100644
--- a/packages/SystemUI/tests/AndroidTest.xml
+++ b/packages/SystemUI/tests/AndroidTest.xml
@@ -16,6 +16,7 @@
 <configuration description="Runs Tests for SystemUI.">
     <target_preparer class="com.android.tradefed.targetprep.TestAppInstallSetup">
         <option name="test-file-name" value="SystemUITests.apk" />
+        <option name="install-arg" value="-t" />
     </target_preparer>
 
     <target_preparer class="com.android.tradefed.targetprep.RootTargetPreparer">