Messaging: Remove GServices

We don't have an actual implementation returning anything but the
defaults, so apply the defaults directly anywhere we need them

Change-Id: Ic651b4b13977799f2f4d2c702c430798fbff77f8

res/values/attrs.xml

@@ -1,6 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <!--
     Copyright (C) 2015 The Android Open Source Project
+    Copyright (C) 2024 The LineageOS Project
 
     Licensed under the Apache License, Version 2.0 (the "License");
     you may not use this file except in compliance with the License.
@@ -57,5 +58,4 @@
             <enum name="subcompact" value="2" />
         </attr>
     </declare-styleable>
-    <attr name="apnPreferenceStyle" format="reference" />
 </resources>