Move unit tests down one level into "unit" folder.

Test: atest NearbyUnitTests
Bug: 214015364
Change-Id: If356bf89ddf49722ecbcc5752320485476b77c2d
diff --git a/nearby/framework/Android.bp b/nearby/framework/Android.bp
index 1f1dac5..74980c9 100644
--- a/nearby/framework/Android.bp
+++ b/nearby/framework/Android.bp
@@ -66,7 +66,7 @@
     visibility: [
         "//packages/modules/Nearby/service",
         "//packages/modules/Nearby/halfsheet",
-        "//packages/modules/Nearby/tests",
+        "//packages/modules/Nearby/tests:__subpackages__",
     ],
 }