add error message when user prematurely submits TO form

atst/routes/task_orders/invite.py

@@ -64,6 +64,7 @@ def invite(task_order_id):
             )
         )
     else:
+        flash("task_order_incomplete")
         return redirect(
             url_for("task_orders.new", screen=4, task_order_id=task_order.id)
         )

atst/utils/flash.py

@@ -128,6 +128,13 @@ MESSAGES = {
         """,
         "category": "success",
     },
+    "task_order_incomplete": {
+        "title_template": "Task Order Incomplete",
+        "message_template": """
+        You must complete your Task Order form before submitting.
+        """,
+        "category": "error",
+    },
 }