Revert "Add BackupEncryption apk as requirement for services"

This reverts commit 38e0e2cc4426b490fa8283dcd5858d658b11af6f.

Reason for revert: Backup Encryption is not being delivered in R, so we should not package this APK with all system images.

Change-Id: I262f04839b7bc314ef451769ccd3ae011ca9c4e7
diff --git a/services/Android.bp b/services/Android.bp
index 60dd895..6953e86 100644
--- a/services/Android.bp
+++ b/services/Android.bp
@@ -47,11 +47,6 @@
         "compat-changeid-annotation-processor",
     ],
 
-    required: [
-      // Required by services.backup
-      "BackupEncryption",
-    ],
-
     // Uncomment to enable output of certain warnings (deprecated, unchecked)
     //javacflags: ["-Xlint"],