Add test ForceL3FallbackPreferenceControllerTest

Bug: 301669353
Test: atest -c ForceL3FallbackPreferenceControllerTest
Change-Id: I182388fa67ac408a2fcf16a6b9599d0971c895d0
diff --git a/tests/unit/Android.bp b/tests/unit/Android.bp
index 327b6aa..9d2d686 100644
--- a/tests/unit/Android.bp
+++ b/tests/unit/Android.bp
@@ -32,6 +32,7 @@
         "kotlinx_coroutines_test",
         "flag-junit",
         "Settings-testutils2",
+        "MediaDrmSettingsFlagsLib",
         // Don't add SettingsLib libraries here - you can use them directly as they are in the
         // instrumented Settings app.
     ],