Fix #12127, 555a379: Truncation ellipses rendered shadows even for black font without shadows

[frosch123]

Motivation / Problem

#12127

Description

Restores the old behavior:

• The first font run decides the font for the ellipses dots.
  • Our string rendering requires the whole string to have a single font, so this is no new/additional restriction.
  • This PR also uses the GetDrawGlyphShadow property of that first font, while previously it used the last font.
• The last font run decides the colour for the ellipses dots.
  • It's always the last run, even if all characters from the last or more runs are completely truncated.

Limitations

It looks as weird as before:

Checklist for review

Some things are not automated, and forgotten often. This list is a reminder for the reviewers.

• The bug fix is important enough to be backported? (label: 'backport requested')
• This PR touches english.txt or translations? Check the guidelines
• This PR affects the save game format? (label 'savegame upgrade')
• This PR affects the GS/AI API? (label 'needs review: Script API')
  • ai_changelog.hpp, game_changelog.hpp need updating.
  • The compatibility wrappers (compat_*.nut) need updating.
• This PR affects the NewGRF API? (label 'needs review: NewGRF')
  • newgrf_debug_data.h may need updating.
  • PR must be added to API tracker