feat(api): Add app_id field to HumanInputForm model

This ensures that `HumanInputForm` could be associated to a specific
application without relying on `WorkflowRun`, providing us a smoother
migration path if we want to implement test form.

api/core/workflow/nodes/human_input/human_input_node.py

@@ -208,6 +208,7 @@ class HumanInputNode(Node[HumanInputNodeData]):
         if form is None:
             display_in_ui = self._display_in_ui()
             params = FormCreateParams(
+                app_id=self.app_id,
                 workflow_execution_id=self._workflow_execution_id,
                 node_id=self.id,
                 form_config=self._node_data,