[Common] Adding 'round' to the INVALID_PROPS list

[badams]

Fixes #2508

Checklist

• Enable CircleCI for your fork
• Include tests

Changes proposed in this pull request:

Add "round" to the list of invalid html props, this will prevent the round prop being passed through to the the HTML Input element here.

Reviewers should focus on:

I've incorporated this prop into the existing tests for this utility function, but not for the InputGroup component itself.

Round does not appear to be a valid html attribute so adding it to this list should be fine

• https://developer.mozilla.org/en-US/docs/Web/HTML/Attributes

[palantirtech]

Thanks for your interest in palantir/blueprint, @badams! 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.

[giladgray]

yes, nice!