Move Slice code to spa/slice folder & add tests.

Bug: 244122804
Test: unit-test & local build gallery
Change-Id: I61baac3e52e1ac3d7b674bc8366bee0074586115
diff --git a/packages/SettingsLib/Spa/testutils/Android.bp b/packages/SettingsLib/Spa/testutils/Android.bp
index 0f618fa..48df569 100644
--- a/packages/SettingsLib/Spa/testutils/Android.bp
+++ b/packages/SettingsLib/Spa/testutils/Android.bp
@@ -24,6 +24,7 @@
     srcs: ["src/**/*.kt"],
 
     static_libs: [
+        "androidx.arch.core_core-runtime",
         "androidx.compose.ui_ui-test-junit4",
         "androidx.compose.ui_ui-test-manifest",
         "mockito",