fix: coerce whitespace strings correctly

[vwong]

What issue does this pull request resolve?

Number/Integer strings with only whitespace gets coerced to 0, when it should be undefined

What changes did you make?

The code already skips coercion on empty zero-length strings, I refined this to skip coercion on strings that are empty after .trim().

Is there anything that requires more attention while reviewing?

No

[vwong]

The CI is broken, but I'm not sure what I would've done to cause it to break. Help?