Add isMobileDataEnabled in TelephonyManager.

Added a new hidden API isMobileDataEnabled in TelephonyManager.
Rename related APIs to isUserMobileDataEnabled,
isUserMobileDataEnabled and setUserMobileDataEnabled to better
clarify their functionality.

Bug: 69814555
Test: build
Change-Id: I2f186f1e7550cafbe4ee3a5af293c39274cbfeaa
diff --git a/core/java/android/net/ConnectivityManager.java b/core/java/android/net/ConnectivityManager.java
index 8071e8b..11d338d 100644
--- a/core/java/android/net/ConnectivityManager.java
+++ b/core/java/android/net/ConnectivityManager.java
@@ -1794,7 +1794,7 @@
                 ITelephony it = ITelephony.Stub.asInterface(b);
                 int subId = SubscriptionManager.getDefaultDataSubscriptionId();
                 Log.d("ConnectivityManager", "getMobileDataEnabled()+ subId=" + subId);
-                boolean retVal = it.getDataEnabled(subId);
+                boolean retVal = it.isUserDataEnabled(subId);
                 Log.d("ConnectivityManager", "getMobileDataEnabled()- subId=" + subId
                         + " retVal=" + retVal);
                 return retVal;