Hide emergency APN in user settings

Emergency APN types is not something for the end user
and should not be possible to edit.

Test: Add an emergency APN and check in Settings
Bug: 207626003
Change-Id: I866eb98dce410218bc76ade3201a2a2abfc959e7

src/com/android/settings/network/apn/ApnSettings.java

@@ -322,6 +322,8 @@ public class ApnSettings extends RestrictedSettingsFragment
         final StringBuilder where =
                 new StringBuilder("NOT (type='ia' AND (apn=\"\" OR apn IS NULL)) AND "
                 + "user_visible!=0");
+        // Remove Emergency type, users should not mess with that
+        where.append(" AND NOT (type='emergency')");
 
         if (mHideImsApn) {
             where.append(" AND NOT (type='ims')");