update to move primary button, change default voice

stream_app.py

@@ -166,6 +166,7 @@ def run_gradio(config:dict):
                         choices=[online_text_model, offline_text_model],
                         value=offline_text_model,
                     )
+                    submit_button = gr.Button("Generate Response", variant='primary')
 
                 with gr.Group():
                     audio_input = gr.Audio(
@@ -194,7 +195,7 @@ def run_gradio(config:dict):
                     with gr.Row():
                         combo_speaker = gr.Dropdown(
                             choices=["alloy", "echo", "fable", "onyx", "nova", "shimmer"], 
-                            show_label=False, value="nova", interactive=True,
+                            show_label=False, value="fable", interactive=True,
                         )
                     with gr.Row():
                         combo_autospeak = gr.Radio(
@@ -210,7 +211,6 @@ def run_gradio(config:dict):
                         )
 
         with gr.Row():
-            submit_button = gr.Button("Generate Response", variant='primary')
             generate_done = gr.State(False)             # is last genai content chunked?
             path_prior = gr.State(None)                 # retain prior file for audio playback
             offset_prior = gr.State(0)                  # track textual offset in genrated content