Revert "Add API method to extract subscription ID from phone account (3/3)"

This reverts commit a31a04bbb762624767ff1cbf787c5fe837a0e842.

Change-Id: Ib6e024854442ffb60246d641c8f935ac111dc362
diff --git a/src/com/android/services/telephony/TelecomAccountRegistry.java b/src/com/android/services/telephony/TelecomAccountRegistry.java
index bbd65cc..b337622 100644
--- a/src/com/android/services/telephony/TelecomAccountRegistry.java
+++ b/src/com/android/services/telephony/TelecomAccountRegistry.java
@@ -256,9 +256,7 @@
                 new ComponentName(phone.getContext(), TelephonyConnectionService.class);
         // TODO: Should use some sort of special hidden flag to decorate this account as
         // an emergency-only account
-        TelecomManager telecomManager = TelecomManager.from(phone.getContext());
-        String id = isEmergency ?
-            "E" : prefix + telecomManager.getPhoneAccountIdForSubscriptionId(phone.getSubId());
+        String id = isEmergency ? "E" : prefix + String.valueOf(phone.getSubId());
         return new PhoneAccountHandle(pstnConnectionServiceName, id);
     }