Stop using deprecated matplotlib and traitlets calls

[schwehr]

python -m unittest discover tests
.....................geemap/cartoee.py:251: MatplotlibDeprecationWarning: The get_cmap function was deprecated in Matplotlib 3.7 and will be removed in 3.11. Use ``matplotlib.colormaps[name]`` or ``matplotlib.colormaps.get_cmap()`` or ``pyplot.get_cmap()`` instead.
  colormap = cm.get_cmap(cmap, n)
..................................geemap/common.py:12787: MatplotlibDeprecationWarning: The get_cmap function was deprecated in Matplotlib 3.7 and will be removed in 3.11. Use ``matplotlib.colormaps[name]`` or ``matplotlib.colormaps.get_cmap()`` or ``pyplot.get_cmap()`` instead.
  cmap = plt.cm.get_cmap(cmap_name, n_class)
..Warning: The folium plotting backend does not support functions in code blocks. Please delete line 8.
...................................................geemap/.venv/lib/python3.13/site-packages/traitlets/traitlets.py:1385: DeprecationWarning: Passing unrecognized arguments to super(Map).__init__(ee_initialize=False).
object.__init__() takes exactly one argument (the instance to initialize)
This is deprecated in traitlets 4.2.This error will be raised in a future release of traitlets.
  warn(

[serenahuang225]

@schwehr Hi is this bug still open? I'm a student in the CodePath AI301 program and I'd like to work on this issue. I'll start by reproducing the problem locally this week. Any pointers on where to start in the codebase would be appreciated!

[schwehr]

Yes, it's still there. It's reasonable to start by asking a chat bot to see if it can explain the errors. I haven't looked into where the warnings are coming from.

[jlzamary]

Hey, another student here interested in working on the issue. Looks like the Matplotlib portion shouldn't be too bad; traitlets might be a little more work.

@serenahuang225 if you're down to split it up or co-author a commit to get the Pair Extraordinaire badge I'd be more than happy to help out.

[alepr]

Hey! I've been working on cleaning up these deprecation warnings. I actually just submitted a PR (#2822) that fixes the get_cmap issues in the build_palette function, and I can try to fix the other errors with get_cmap too.

@serenahuang225 @jlzamary, feel free to check that PR out.