Fix: Incorrect button size for "larger toolbars"

[WenSimEHRP]

Motivation / Problem

The button entry for "bigger main toolbar" in the settings menu is set incorrectly,
misplacing the button.

Description

Fix this problem by rearranging the UI elements.

Limitations

None that I can think of.

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

[JGRennison]

Thanks :)