fix: Remove error when a future client is not available to warn instead

Author: Robin VAN DE MERGHEL

src/DIRAC/Core/Tornado/Client/ClientSelector.py

@@ -66,14 +66,13 @@ def ClientSelector(disetClient, *args, **kwargs):  # We use same interface as RP
         # If we are not already given a URL, resolve it
         if serviceName.startswith(("http", "dip")):
             completeUrl = serviceName
-        elif useLegacyAdapter(serviceName):
-            sLog.debug(f"Using legacy adapter for service {serviceName}")
-            if diracxClient is None:
-                raise NotImplementedError(
-                    "DiracX is enabled but no diracxClient is provided, do you need to update your client?"
-                )
+        elif useLegacyAdapter(serviceName) and diracxClient is not None:
             return diracxClient()
         else:
+            if diracxClient:
+                # Only warn to deactivate it without making the code crash.
+                sLog.warn("DiracX is enabled but no diracxClient is provided, do you need to update your client?")
+
             completeUrl = getServiceURL(serviceName)
             sLog.debug(f"URL resolved: {completeUrl}")