Test warnings

[leehart]

Just to note some warnings that appear during routine tests that should probably be addressed at some point:

tests/anoph/test_dipclust.py: 37 warnings
  site-packages/plotly/basedatatypes.py:2314: DeprecationWarning:
  
  The append_trace method is deprecated and will be removed in a future version.
  Please use the add_trace method with the row and col parameters.

WARNING  traitlets:interaction.py:250 Exception in interact callback:  Parameter 'variant' with value None in call to function
'plot_frequencies_map_markers' has incorrect type: found None,
expected int or str. See below for further information.

None did not match any element in the union:
  int: is not an instance of int
  str: is not an instance of str
Traceback (most recent call last):
  File "site-packages/ipywidgets/widgets/interaction.py", line 243, in update
    self.result = self.f(**self.kwargs)
                  ^^^^^^^^^^^^^^^^^^^^^
  File "malariagen-data-python/malariagen_data/util.py", line 1163, in check_types_wrapper
    raise error from None
TypeError:  Parameter 'variant' with value None in call to function
'plot_frequencies_map_markers' has incorrect type: found None,
expected int or str. See below for further information.

None did not match any element in the union:
  int: is not an instance of int
  str: is not an instance of str