fix: groupchat needs more than 2 agents

Signed-off-by: nolan <nolan@exvul.com>

swarms/structs/groupchat.py

@@ -248,8 +248,8 @@ class GroupChat:
         Raises:
             ValueError: If any required components are missing or invalid
         """
-        if not self.agents:
-            raise ValueError("No agents provided")
+        if len(self.agents)<2:
+            raise ValueError("At least two agents are required for a group chat")
         if self.speaker_fn is None:
             raise ValueError("No speaker function provided")
         if self.max_loops <= 0: