Expose unselectCell on DataGrid handle

[marcellofuschi]

Working with DataGrid I found myself needing to unselect the selected cell (when the user moves focus to an external element)

[codecov-commenter]

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Codecov Report

❌ Patch coverage is 0% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 97.09%. Comparing base (17d564b) to head (0135d78).

Files with missing lines	Patch %	Lines
src/DataGrid.tsx	0.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3927      +/-   ##
==========================================
- Coverage   97.34%   97.09%   -0.25%     
==========================================
  Files          36       36              
  Lines        1169     1172       +3     
  Branches      345      345              
==========================================
  Hits         1138     1138              
- Misses         31       34       +3     

Files with missing lines	Coverage Δ
src/DataGrid.tsx	98.10% <0.00%> (-0.71%)	⬇️

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[amanmahajan7]

The selection outline persists even when the cell is not focused. We can do the following to show the outline only on focused cells? Does that work for you or the intention is to actually clear the selected position?

<DataGrid className="my-class" ../>

.my-class {
  .rdg-cell[aria-selected='true'] {
    outline: none;
  }

  .rdg-cell:focus {
    outline: var(--rdg-selection-width) solid var(--rdg-selection-color);
  }
} 

https://github.com/Comcast/react-data-grid/blob/main/src/style/cell.ts#L25