Reduced small Select's content height to be consistent with small ComboBox

[smmr-dn]

Changes

As user reported the issue regarding the height difference between small ComboBox and Select, this PR reduced the min-block-size and line-height of the content inside small Select to --iui-size-m so that the overall height would not exceed 24px.

Before	After

Testing

Approved test screenshots.

Docs

Added changesets for itwinui-react and itwinui-css packages.

[mayank99]

Please fix the centering. There shouldn't be any test image changes in stories that don't use the small Select.

[smmr-dn]

Please fix the centering. There shouldn't be any test image changes in stories that don't use the small Select.

I figured when I used the fallback values (--iui-size-l) for min-block-size and line-height for other sizes, it returned 21px instead of 24px, which eventually caused the texts to be un-centered. I tried specifying the min-block-size and line-height vars for medium and large size. The screenshots have been corrected as well.

[mayank99]

LGTM