Add running project check for fast duplication

gns3server/controller/project.py

@@ -1334,9 +1334,6 @@ class Project:
         self.dump()
         assert self._status != "closed"
 
-        if self.is_running():
-            raise ControllerError("Project must be stopped in order to duplicate it")
-
         try:
             proj = await self._fast_duplication(name, reset_mac_addresses)
             if proj: