Add filegroup for telephony file context

Add a filegroup for telephony so that it can be shared between the main
telephony apex and the one used for testing.

Bug: 145232009
Test: atest telephony_e2e_tests
Change-Id: I5e20d7b7fc30d2c28de8f339c7b4722e1e438e17
diff --git a/apex/Android.bp b/apex/Android.bp
index 19a44c7..cbf9b63 100644
--- a/apex/Android.bp
+++ b/apex/Android.bp
@@ -133,6 +133,13 @@
 }
 
 filegroup {
+  name: "com.android.telephony-file_contexts",
+  srcs: [
+    "com.android.telephony-file_contexts",
+  ],
+}
+
+filegroup {
   name: "com.android.tzdata-file_contexts",
   srcs: [
     "com.android.tzdata-file_contexts",