Fix/colang 2/flow continuation prompt

nemoguardrails/llm/prompts/llama3.yml

@@ -316,6 +316,7 @@ prompts:
       messages:
         - type: system
           content: "Directly response with expected answer. Don't provide any pre- or post-explanations."
-        - type: user
+
+        - type: system
           content: |-
               {{ flow_nld }}

nemoguardrails/llm/prompts/openai-chatgpt.yml

@@ -222,7 +222,7 @@ prompts:
         content: "This is the current conversation between the user and the bot:"
       - "{{ history | colang | to_messages_v2}}"
 
-      - type: assistant
+      - type: system
         content: |
           Follow these instruction `{{ instructions }}` to generate a value that is assigned to:
           ${{ var_name }} =
@@ -303,6 +303,6 @@ prompts:
       - openai/gpt-3.5-turbo
       - openai/gpt-4
     messages:
-      - type: user
+      - type: system
         content: |-
             {{ flow_nld }}

tests/v2_x/test_state_serialization.py

@@ -119,7 +119,7 @@ async def test_serialization():
         avg_time += took
     avg_time /= number_of_runs
 
-    assert avg_time < 0.1
+    assert avg_time < 0.2
 
     assert isinstance(s, str)