Robustify the coloring

[EmmaRenauld]

Quick description

In some cases, the hidden _data is not ordered correctly. Ex:

new_order = np.flip(np.arange(len(sft)))
sft = sft[new_order]

The sft.data_per_point[key]._data is not always updated!

Accessing the data directly instead.

! Note: There are many other _data usage in that file. I didn't test them all.

It also made me notice that the test name was not correct.
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Type of change

Check the relevant options.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Provide data, screenshots, command line to test (if relevant)

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Checklist

• My code follows the style guidelines of this project (run autopep8)
• I added relevant citations to scripts, modules and functions docstrings and descriptions
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I moved all functions from the script file (except the argparser and main) to scilpy modules
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[arnaudbore]

Build passed ! Good Job 🍻 !

[arnaudbore]

GTG