Changes to layouts.json can be saved separately from saving the actual map.bin, which can lead to incorrect sizes

[Sierraffinity]

Steps to repro:

1. Change size of layout on map 1; don't save
2. Go to map 2, change layout, and save
3. Observe that in layouts.json, the size of the layout for map 1 has changed
4. Cancel changes to layout 1 by reloading project, or exiting Porymap
5. Observe that map 1 has loaded the bin file incorrectly due to the layout being the wrong size