Fix permission checking for a11y volume.

Adding new permission for changing accessibility volume
to allow system UI to change it. Also providing audio
manager with a whitelist of bound accessibility service
uids so it can allow servics to change the volume.

Bug: 36569297
Test: Adding CTS test in linked CL.
Change-Id: I4f327e3a251fc3780c5957f41217c2ef5bb8b16e
diff --git a/packages/SystemUI/AndroidManifest.xml b/packages/SystemUI/AndroidManifest.xml
index e4d71b6..1147f16 100644
--- a/packages/SystemUI/AndroidManifest.xml
+++ b/packages/SystemUI/AndroidManifest.xml
@@ -181,7 +181,7 @@
     <uses-permission android:name="android.permission.MODIFY_ACCESSIBILITY_DATA" />
 
     <!-- to control accessibility volume -->
-    <uses-permission android:name="android.permission.BIND_ACCESSIBILITY_SERVICE" />
+    <uses-permission android:name="android.permission.CHANGE_ACCESSIBILITY_VOLUME" />
 
     <application
         android:name=".SystemUIApplication"