The text under previews would be quite close to the preview, so that
there was more space below it than above. Center it vertically in the
available space now. Also, the horizontal padding was only applied to
the right side of the text rectangle, meaning horizontally centered text
would be too far left. Apply the padding equally, this doesn't affect
available space for the text too much.
See #108018 for before/after pictures.
Pull Request: https://projects.blender.org/blender/blender/pulls/108018
c89354da80