build(deps): Bump mtui_mod from 2645355 to a32aa25

Bumps [mtui_mod](https://github.com/minetest-go/mtui_mod) from `2645355` to `a32aa25`.
- [Commits](minetest-go/mtui_mod@2645355...a32aa25)

---
updated-dependencies:
- dependency-name: mtui_mod
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>