Convert SettingsProxy and UserSettingsProxy to Kotlin.

Conversion to Kotlin is the first step towards migrating
register/unregister content observer APIs to background thread.

Test: atest / manual flash
Bug: 330299944
Flag: NONE Java to Kotlin migration, flag not needed.
Change-Id: I793d4bd9ad3d6ac9e39c3e97b7e4edc5b794ba84
diff --git a/packages/SystemUI/Android.bp b/packages/SystemUI/Android.bp
index 8b60ed0..c4929a1 100644
--- a/packages/SystemUI/Android.bp
+++ b/packages/SystemUI/Android.bp
@@ -766,6 +766,7 @@
     ],
     static_libs: [
         "RoboTestLibraries",
+        "mockito-kotlin2",
     ],
     libs: [
         "android.test.runner",