Fix color_map setting in visualization notebook

[camisowers]

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What is the purpose of this PR?

Closes #1040. Allows users to change the colormap used for the dimensionality reduction plotting.

How did you implement your changes

The wrapper function visualize_dimensionality_reduction() was not actually passing the inputted color_map to plot_dim_reduced_data().

Remaining issues

• [x] test notebook plotting with new color map