polars xlsx_cells

[samukweku]

PR Description

Please describe the changes proposed in the pull request:

• xlsx_cells now supports polars.

jn.xlsx_cells('../Downloads/worked-examples.xlsx',engine='polars',sheetnames='highlights',fill=True).get_column('fill')
Out[101]: 
shape: (8,)
Series: 'fill' [struct[3]]
[
        {null,{"00000000","rgb",0.0},{"00000000","rgb",0.0}}
        {null,{"00000000","rgb",0.0},{"00000000","rgb",0.0}}
        {null,{"00000000","rgb",0.0},{"00000000","rgb",0.0}}
        {null,{"00000000","rgb",0.0},{"00000000","rgb",0.0}}
        {"solid",{"FFFFFF00","rgb",0.0},{"FFFFFF00","rgb",0.0}}
        {"solid",{"FFFFFF00","rgb",0.0},{"FFFFFF00","rgb",0.0}}
        {null,{"00000000","rgb",0.0},{"00000000","rgb",0.0}}
        {null,{"00000000","rgb",0.0},{"00000000","rgb",0.0}}
]

This PR relates to #1352.

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Relevant Reviewers

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• @ericmjl

[ericmjl]

🚀 Deployed on https://deploy-preview-1358--pyjanitor.netlify.app

[ericmjl]

@samukweku what are your thoughts on assigning base_engine whenever we dispatch differently between polars and pandas? Does it make sense for us to use one pattern instead?

[ericmjl]

I'm approving the PR, knowing that there is a question to be resolved nonetheless. I think we should continue it on an issue tracker.