[RN] Allow to override callHandle for CallKit (coding style)

react/features/base/config/functions.js

     'callDisplayName',
 
     /**
-     * The call handle of the CallKit call representing the conference/meeting
-     * associated with this config.js. The property is meant for use cases in
-     * which Jitsi Meet is to work with a CallKit call created outside of Jitsi
-     * Meet and to be adopted by Jitsi Meet such as, for example, an incoming
-     * and/or outgoing CallKit call created by Jitsi Meet SDK for iOS
-     * clients/consumers prior to giving control to Jitsi Meet. As the value is
+     * The handle
+     * ({@link https://developer.apple.com/documentation/callkit/cxhandle}) of
+     * the CallKit call representing the conference/meeting associated with this
+     * config.js. The property is meant for use cases in which the room URL is
+     * not desirable as the handle for CallKit purposes. As the value is
      * associated with a conference/meeting, the value makes sense not as a
      * deployment-wide configuration, only as a runtime configuration
      * override/overwrite provided by, for example, Jitsi Meet SDK for iOS.

react/features/mobile/callkit/middleware.js

 
     const { conference } = action;
     const state = getState();
-    const { callUUID, callHandle } = state['features/base/config'];
+    const { callHandle, callUUID } = state['features/base/config'];
     const url = getInviteURL(state);
+    const handle = callHandle || url.toString();
     const hasVideo = !isVideoMutedByAudioOnly(state);
 
     // When assigning the call UUID, do so in upper case, since iOS will return
     // it upper cased.
     conference.callUUID = (callUUID || uuid.v4()).toUpperCase();
 
-    const handleURL = callHandle || url.toString();
-
-    CallKit.startCall(conference.callUUID, handleURL, hasVideo)
+    CallKit.startCall(conference.callUUID, handle, hasVideo)
         .then(() => {
             const { callee } = state['features/base/jwt'];
             const displayName