Switch to source-built GSON.

Bug: 243950468
Test: local build, presubmit, check that aosp_raven boots.
Change-Id: I63f3bd3b99379ff21f5276bdaa19ecca23fcf6e8
diff --git a/android/app/tests/unit/Android.bp b/android/app/tests/unit/Android.bp
index 5d0302f..4e68385 100755
--- a/android/app/tests/unit/Android.bp
+++ b/android/app/tests/unit/Android.bp
@@ -20,12 +20,12 @@
     static_libs: [
         "androidx.test.ext.truth",
         "androidx.test.rules",
-        "mockito-target",
         "androidx.test.espresso.intents",
-        "gson-prebuilt-jar",
         "androidx.room_room-migration",
         "androidx.room_room-runtime",
         "androidx.room_room-testing",
+        "gson",
+        "mockito-target",
         "truth-prebuilt",
         "PlatformProperties"
     ],