[Spa] Use Mockito Kotlin

So MockitoHelper can be clean up.

Bug: 289155281
Test: Gradle Sync
Test: unit test
Change-Id: I1a6367639a75499f34cdcb0384b99544bd079285
diff --git a/packages/SettingsLib/Spa/testutils/Android.bp b/packages/SettingsLib/Spa/testutils/Android.bp
index 65f5d34..4031cd7 100644
--- a/packages/SettingsLib/Spa/testutils/Android.bp
+++ b/packages/SettingsLib/Spa/testutils/Android.bp
@@ -30,7 +30,7 @@
         "androidx.compose.ui_ui-test-junit4",
         "androidx.compose.ui_ui-test-manifest",
         "androidx.lifecycle_lifecycle-runtime-testing",
-        "mockito",
+        "mockito-kotlin2",
         "truth-prebuilt",
     ],
     kotlincflags: [