[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/build.gradle.kts b/packages/SettingsLib/Spa/testutils/build.gradle.kts
index f5a22c9..50243dc 100644
--- a/packages/SettingsLib/Spa/testutils/build.gradle.kts
+++ b/packages/SettingsLib/Spa/testutils/build.gradle.kts
@@ -41,7 +41,12 @@
     api("androidx.arch.core:core-testing:2.2.0-alpha01")
     api("androidx.compose.ui:ui-test-junit4:$jetpackComposeVersion")
     api("androidx.lifecycle:lifecycle-runtime-testing")
+    api("org.mockito.kotlin:mockito-kotlin:5.1.0")
+    api("org.mockito:mockito-core") {
+        version {
+            strictly("2.28.2")
+        }
+    }
     api(libs.truth)
-    api("org.mockito:mockito-core:2.21.0")
     debugApi("androidx.compose.ui:ui-test-manifest:$jetpackComposeVersion")
 }