BUG-26214 fix colors parameter in DataFrame.boxplot
- [X] closes #26214
- [X] tests added / passed
- [X] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [X] whatsnew entry

This PR fixes issues in the handling of the `color` parameter in the implementation of `DataFrame.boxplot` that do not exist in `DataFrame.plot.box`

- the `color` parameter is now removed from `kwds` before the `matplotlib` call, preventing an error
- an alternative implementation of color extraction from `color`, as `_get_standard_colors` did not preserve the appropriate order (without looking at that function, one can see that the previous implementation would give the boxes and the medians the same color even when otherwise specified)
- checking that `color` is actually a `dict`
