Remove displaying of WifiCalling twice in Settings search.

+ WifiCalling was getting displayed twice due to addition of
WifiCallingSettings screen in Settings ranking & index files.
+ This also solves issue of displaying WifiCalling option in non supported
carrier/platform.

Bug: 25669303
Change-Id: I179128d1f3c876a4d3f826e0365cbb2b761d57dd