Upgrade robolectric to /external/robolectric to prep for removal of /external/robolectric shadows.

Bug: 261728063
Test: atest CarSetupWizardLibRoboTests

Git diff of test summary was identical.

Change-Id: Iff8351916162667fbf95942a6de6285cd251ed70
diff --git a/library/main/tests/robotests/Android.bp b/library/main/tests/robotests/Android.bp
index 9d91639..5adead1 100644
--- a/library/main/tests/robotests/Android.bp
+++ b/library/main/tests/robotests/Android.bp
@@ -34,4 +34,5 @@
     ],
 
     instrumentation_for: "CarSetupWizardLib",
+    upstream: true,
 }