fix: Improve tenant listing by handling non-string results and simplifying list processing

Website/server_steering.py

@@ -375,14 +375,12 @@ class instace:
         - list with all tenants ("tenant1", "tenant2")
         """            
         result = execute_script(_var, _cmd, "list")
+        if not isinstance(result, str):
+            return []
         result = result.splitlines()
-        result.pop(0)
-        counter = 0
-        for i in result:
-            i = i.replace("- ", "")
-            result[counter] = i
-            counter += 1
-        return result
+        if not result:
+            return []
+        return [line.replace("- ", "") for line in result[1:]]
 
     def backup(name: str) -> bool:
         """