Feat: add mechanism to check cancellation in Agent (#10766)

### What problem does this PR solve?

Add mechanism to check cancellation in Agent.

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

agent/component/iteration.py

@@ -56,6 +56,9 @@ class Iteration(ComponentBase, ABC):
                 return cid
 
     def _invoke(self, **kwargs):
+        if self.check_if_canceled("Iteration processing"):
+            return
+
         arr = self._canvas.get_variable_value(self._param.items_ref)
         if not isinstance(arr, list):
             self.set_output("_ERROR", self._param.items_ref + " must be an array, but its type is "+str(type(arr)))