Migrate flag config_telephony_use_own_number_for_voicemail to Carrier Config.

Bug: 65683508
Test: Basic telephony sanity
Change-Id: I3ff7d5726193a554a8154bd13bbfd347c89b6a99
diff --git a/telephony/java/android/telephony/CarrierConfigManager.java b/telephony/java/android/telephony/CarrierConfigManager.java
index 47b0f79..32db9f7 100644
--- a/telephony/java/android/telephony/CarrierConfigManager.java
+++ b/telephony/java/android/telephony/CarrierConfigManager.java
@@ -346,6 +346,17 @@
     public static final String KEY_DEFAULT_VM_NUMBER_STRING = "default_vm_number_string";
 
     /**
+     * Flag that specifies to use the user's own phone number as the voicemail number when there is
+     * no pre-loaded voicemail number on the SIM card.
+     * <p>
+     * {@link #KEY_DEFAULT_VM_NUMBER_STRING} takes precedence over this flag.
+     * <p>
+     * If false, the system default (*86) will be used instead.
+     */
+    public static final String KEY_CONFIG_TELEPHONY_USE_OWN_NUMBER_FOR_VOICEMAIL_BOOL =
+            "config_telephony_use_own_number_for_voicemail_bool";
+
+    /**
      * When {@code true}, changes to the mobile data enabled switch will not cause the VT
      * registration state to change.  That is, turning on or off mobile data will not cause VT to be
      * enabled or disabled.
@@ -1639,6 +1650,7 @@
         sDefaults.putBoolean(KEY_NOTIFY_HANDOVER_VIDEO_FROM_WIFI_TO_LTE_BOOL, false);
         sDefaults.putBoolean(KEY_SUPPORT_DOWNGRADE_VT_TO_AUDIO_BOOL, true);
         sDefaults.putString(KEY_DEFAULT_VM_NUMBER_STRING, "");
+        sDefaults.putBoolean(KEY_CONFIG_TELEPHONY_USE_OWN_NUMBER_FOR_VOICEMAIL_BOOL, false);
         sDefaults.putBoolean(KEY_IGNORE_DATA_ENABLED_CHANGED_FOR_VIDEO_CALLS, true);
         sDefaults.putBoolean(KEY_VILTE_DATA_IS_METERED_BOOL, true);
         sDefaults.putBoolean(KEY_CARRIER_WFC_IMS_AVAILABLE_BOOL, false);