PLT-2600/PLT-2770 Changed getPublicLink api call to return a proper JSON string (#2914)

* Removed unused channelId and userId parameters from web client getPublicLink method

* Changed getPublicLink api call to return a proper JSON string

api/file.go

@@ -529,7 +529,7 @@ func getPublicLink(c *Context, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	w.Write([]byte(url))
+	w.Write([]byte(model.StringToJson(url)))
 }
 
 func getExport(c *Context, w http.ResponseWriter, r *http.Request) {