Fix too thin underline in brace match

[KoBeWi]

Fixes #60001

[bruvzg]

Probably should be also multiplied by editor scale:

MAX(font->get_underline_thickness(font_size) * get_theme_default_base_scale(), 1));

[bruvzg]

If underline thickness can be less than one, the same changes should be added to the RTL and LinkButton as well, since they might have the same issue.

[KoBeWi]

The problem seems to occur only in TextEdit, at least with the default theme.

[akien-mga]

Thanks!