sdl2: theme_default_font_size adjustments do not match adjustments of other fonts
S3_0 patch meant also to S2_6 (while this is not a critical bug to fix in S2_6, later patches likely benefit from having this in the baseline)
Can be pushed to branches other than S3_0 already, S3_0 only after 3.0.7 release.
When sdl2-client create_utf8_str() ends to using theme defined font size, it does not do adj_font() to it. Arguable, but I think we should treat the theme provided font size to be relative to other elements, so when we adjust everything else we should also adjust that one.
I don't think this is currently user-visible though; the adjustment is never used in practice (there's no way to enable small screen mode), and I suspect that theme provided font size is not used at all (-> going to open a new ticket about this)