Remove wifiConfiguration.isVisibleToUser()

This method seemed like a good idea at the time (quickly check whether a
network configuration is visible to a given user). However, once managed
profiles come into play, this simple method is no longer appropriate.
There is a more comprehensive replacement at
com.android.server.wifi.WifiConfigurationUtil.isVisibleToAnyProfile()
now and this method here can go.

BUG:26867426

Change-Id: Ia66aa6f74003a16eca24c5088d3aba8e0c9f8140

wifi/java/android/net/wifi/WifiConfiguration.java

@@ -1754,11 +1754,6 @@ public class WifiConfiguration implements Parcelable {
         return 0;
     }
 
-    /** @hide */
-    public boolean isVisibleToUser(int userId) {
-        return shared || (UserHandle.getUserId(creatorUid) == userId);
-    }
-
     /** @hide */
     public void setPasspointManagementObjectTree(String passpointManagementObjectTree) {
         mPasspointManagementObjectTree = passpointManagementObjectTree;