Use new robolectric in /external/mobile-data-download/javatests

Test: atest -c MobileDataDownloadRoboTests in //external/mobile-data-download/javatests
Bug: 261728063
Change-Id: Iedba3f58dc794e2be67472f1c4cf7ed13b8038d6
diff --git a/Android.bp b/Android.bp
index 84d7af2..435b473 100644
--- a/Android.bp
+++ b/Android.bp
@@ -171,6 +171,7 @@
     libs: ["Robolectric_all_upstream"],
     visibility: [
         "//platform_testing/robolab/roboStandaloneProj/tests",
+        "//external/mobile-data-download/javatests"
     ],
 }