fix: tools page on playground resets agent after every interaction (#2044)

# What does this PR do?

This PR updates how the `AgentType` gets set using the radio button on
the tools page of the playground. This change is needed due to the fact
with its current implementation, the chat interface will resets after
every input, preventing users from having a multi-turn conversation with
the agent.

## Test Plan

Run the Playground without these changes:
```bash
streamlit run llama_stack/distribution/ui/app.py
```
Navigate to the tools page and attempt to have a multi-turn
conversation. You should see the conversation reset after asking a
second question.

Repeat the steps above with these changes and you will see that it works
as expected when asking the agent multiple questions.

Signed-off-by: Michael Clifford <mcliffor@redhat.com>

llama_stack/distribution/ui/page/playground/tools.py

@@ -94,12 +94,16 @@ def tool_chat_page():
         st.subheader("Agent Configurations")
         st.subheader("Agent Type")
         agent_type = st.radio(
-            "Select Agent Type",
-            [AgentType.REGULAR, AgentType.REACT],
-            format_func=lambda x: x.value,
+            label="Select Agent Type",
+            options=["Regular", "ReAct"],
             on_change=reset_agent,
         )
 
+        if agent_type == "ReAct":
+            agent_type = AgentType.REACT
+        else:
+            agent_type = AgentType.REGULAR
+
         max_tokens = st.slider(
             "Max Tokens",
             min_value=0,