docs: changed call[0] to calls[0] in docs (#1540)

Author: softwarebyze

packages/react-native-sdk/docusaurus/docs/reactnative/04-ui-components/call/incoming-call.mdx

@@ -42,7 +42,7 @@ const Call = () => {
   const calls = useCalls();
 
   return (
-    <StreamCall call={call[0]}>
+    <StreamCall call={calls[0]}>
       <CallPanel />
     </StreamCall>
   );