The difference in width compared to the popup is due to the potentially
different widths of the dedicated icons/styleboxes.
Make the width at least the width of the popup.
This allows removing it from `class_db.h`, significantly reducing the amount of files
that include it transitively.
Also includes some include cleanup in `control.h` and `rich_text_label.h` done while
ensure they don't depend on `callable_mp`.
风青山
Rémi Verschelde
Thaddeus Crews
Aaron Franke
Pāvels Nadtočajevs
Haoyu Qiu
kobewi
Micky
Bastiaan Olij