isTetherApnRequired api rename as isTetheringApnRequired

Bug: 144455789
Test: Build pass.
      atest TetheringConfigurationTest (PASS)

Change-Id: I5495b7ae25eae888d5c719746a9afabcf0aeb5cb
diff --git a/src/com/android/phone/PhoneInterfaceManager.java b/src/com/android/phone/PhoneInterfaceManager.java
index 3ddb267..0ed2a7a 100755
--- a/src/com/android/phone/PhoneInterfaceManager.java
+++ b/src/com/android/phone/PhoneInterfaceManager.java
@@ -4900,7 +4900,7 @@
      * @hide
      */
     @Override
-    public boolean isTetherApnRequiredForSubscriber(int subId) {
+    public boolean isTetheringApnRequiredForSubscriber(int subId) {
         enforceModifyPermission();
         final long identity = Binder.clearCallingIdentity();
         final Phone phone = getPhone(subId);