[table] fix(Cell): only modify props for specific child elements

[dalaicam]

Console message: "Warning: React does not recognize the parentCellWidth prop on a DOM element. If you intentionally want it to appear in the DOM as a custom attribute, spell it as lowercase parentcellwidth instead. If you accidentally passed it from a parent component, remove it from the DOM element."

Fixes #0000

Checklist

• Includes tests
• Update documentation

Changes proposed in this pull request:

Reviewers should focus on:

Screenshot

[palantirtech]

Thanks for your interest in palantir/blueprint, @dalaicam! Before we can accept your pull request, you need to sign our contributor license agreement - just visit https://cla.palantir.com/ and follow the instructions. Once you sign, I'll automatically update this pull request.

[adidahiya]

Can you further describe your issue? What is the use case here? Can you demonstrate it in a code sandbox? Can you add a unit test for this change?

[dalaicam]

This is minor issue/fix as doesn't seem to influence the behavior other than filling up the console with warnings.

To replicate, simply add a button to Cell component, not sure if affects other components. Tho, based on the comment and the if conditions it should only affect the TruncatedFormat and JSONFormat.
The if, as it is (before this change), affects all components.

Code example of issue:
https://codesandbox.io/s/blueprint-sandbox-4sf1t

[muratbeser]

I'm also effected by this issue.