The String to Curves node allows selecting various metrics for the
characters. Size is the absolute height between two lines, and is
correctly marked as a distance. Character, Word and Line Spacing, on
the other hand, do not represent any distance, but are proportional to
the base size and should not have distance units.
This commit simply removes the properties' `PROP_DISTANCE` subtype.
Pull Request: https://projects.blender.org/blender/blender/pulls/106660
4f08eeae9c