Make wifi calling slice consistent

The wifi calling search result is grayed out if it is not using
carrier WFC. In order to ensure the search result is aligned with the
corresponding settings, the checker of wifi calling slice will be the
same with wifi calling preference.

Bug: 285594611
Test: manual test
Change-Id: I22d794332a0cc2ecbcb8b5e8836364e926400cbf

tests/robotests/src/com/android/settings/network/ims/MockWifiCallingQueryImsState.java

@@ -29,6 +29,7 @@ public class MockWifiCallingQueryImsState extends WifiCallingQueryImsState {
     private Boolean mIsProvisionedOnDevice;
     private Boolean mIsServiceStateReady;
     private Boolean mIsEnabledByUser;
+    private Boolean mIsReadyToWifiCalling;
 
     /**
      * Constructor
@@ -103,4 +104,16 @@ public class MockWifiCallingQueryImsState extends WifiCallingQueryImsState {
         return super.isEnabledByUser(subId);
     }
 
+    public void setIsReadyToWifiCalling(boolean isReady) {
+        mIsReadyToWifiCalling = isReady;
+    }
+
+    @Override
+    public boolean isReadyToWifiCalling() {
+        if (mIsReadyToWifiCalling != null) {
+            return mIsReadyToWifiCalling;
+        }
+        return super.isReadyToWifiCalling();
+    }
+
 }