Use Telecom API for checking if a number is voicemail (1/2)

Since we don't want to communicate directly with Telephony in dialer, call
PhoneNumberUtils.isVoiceMailNumber (a Telephony method) through the
Telecom API. Add a method in TelecomManager to do this.

Bug: 17925501

Change-Id: Iecea82a0e5f0b106eaf105e9026d606110acf122
diff --git a/telecomm/java/com/android/internal/telecom/ITelecomService.aidl b/telecomm/java/com/android/internal/telecom/ITelecomService.aidl
index f1cf885..91f44b9 100644
--- a/telecomm/java/com/android/internal/telecom/ITelecomService.aidl
+++ b/telecomm/java/com/android/internal/telecom/ITelecomService.aidl
@@ -115,6 +115,11 @@
     void clearAccounts(String packageName);
 
     /**
+     * @see TelecomServiceImpl#isVoiceMailNumber
+     */
+    boolean isVoiceMailNumber(in PhoneAccountHandle accountHandle, String number);
+
+    /**
      * @see TelecomServiceImpl#getDefaultPhoneApp
      */
     ComponentName getDefaultPhoneApp();