Fix final_answer assignment and update image content handling in stream_to_gradio function

Gradio_UI.py

@@ -153,7 +153,7 @@ def stream_to_gradio(
         ):
             yield message
 
-    final_answer = step_log  # Last log is the run's final_answer
+    final_answer = step_log.final_answer  # Last log is the run's final_answer
     final_answer = handle_agent_output_types(final_answer)
 
     if isinstance(final_answer, AgentText):
@@ -165,7 +165,7 @@ def stream_to_gradio(
         yield gr.ChatMessage(
             role="assistant",
             # content={"path": final_answer.to_string(), "mime_type": "image/png"},
-            content=gr.Image(str(final_answer.final_answer)),
+            content=gr.Image(str(final_answer)),
             metadata={"mime_type": "image/png"},
         )
     elif isinstance(final_answer, AgentAudio):