Change SystemApi as per API council feedback

API council have requested a manifest constant be added
to the SystemApi directly in preference to an indirect
SystemApi constant here:
android.provider.TimeZoneRulesDataContract.READER_PERMISSION.

This is the third of three changes to (1) add the new constant,
(2) switch over code using the constant, (3) remove the old
constant.

Bug: 64568899
Test: None, build only
Change-Id: I75731b13ce2046556d6148aa5707cab6ed9cf9bf

api/system-current.txt

@@ -38659,7 +38659,6 @@ package android.provider {
 
   public final class TimeZoneRulesDataContract {
     field public static final java.lang.String AUTHORITY = "com.android.timezone";
-    field public static final java.lang.String READER_PERMISSION = "android.permission.UPDATE_TIME_ZONE_RULES";
   }
 
   public static final class TimeZoneRulesDataContract.Operation {

core/java/android/provider/TimeZoneRulesDataContract.java

@@ -40,12 +40,6 @@ public final class TimeZoneRulesDataContract {
     /** A content:// style uri to the authority for the time zone data content provider */
     private static final Uri AUTHORITY_URI = Uri.parse("content://" + AUTHORITY);
 
-    /**
-     * The permission that the reader of the ContentProvider must possess.
-     */
-    public static final String READER_PERMISSION =
-            android.Manifest.permission.UPDATE_TIME_ZONE_RULES;
-
     /**
      * Defines fields exposed through the {@link Operation#CONTENT_URI} for describing a time zone
      * distro operation.