Update vis to use ffmpeg

[rusu24edward]

LC Toss 4 supports ffmpeg now, so I should update the viz to use it.

After #395
Related to #400

[rusu24edward]

Need to make sure to only start the animation once the figure is added to the FigureCanvasTkAgg

  File "/g/g13/rusu1/abmarl/abmarl/stage.py", line 160, in visualize
    anim.save(
  File "/g/g13/rusu1/v_abmarl_39/lib/python3.9/site-packages/matplotlib/animation.py", line 1092, in save
    anim._init_draw()  # Clear the initial frame
  File "/g/g13/rusu1/v_abmarl_39/lib/python3.9/site-packages/matplotlib/animation.py", line 1749, in _init_draw
    self._draw_frame(frame_data)
  File "/g/g13/rusu1/v_abmarl_39/lib/python3.9/site-packages/matplotlib/animation.py", line 1768, in _draw_frame
    self._drawn_artists = self._func(framedata, *self._args)
  File "/g/g13/rusu1/abmarl/abmarl/stage.py", line 143, in animate
    plt.pause(1e-16)
  File "/g/g13/rusu1/v_abmarl_39/lib/python3.9/site-packages/matplotlib/pyplot.py", line 662, in pause
    show(block=False)
  File "/g/g13/rusu1/v_abmarl_39/lib/python3.9/site-packages/matplotlib/pyplot.py", line 527, in show
    return _get_backend_mod().show(*args, **kwargs)
  File "/g/g13/rusu1/v_abmarl_39/lib/python3.9/site-packages/matplotlib/backend_bases.py", line 3435, in show
    manager.show()  # Emits a warning for non-interactive backend.
  File "/g/g13/rusu1/v_abmarl_39/lib/python3.9/site-packages/matplotlib/backends/_backend_tk.py", line 559, in show
    self.canvas.manager.window.attributes('-topmost', 1)
AttributeError: 'NoneType' object has no attribute 'window'