Test: Grid Editor Layout smoke test

[bpasero]

• any os @stevencl
• any os @rebornix

Complexity: 3

The grid editor layout feature was already tested last milestone extensively (see #50458) but there were still quite a bit of changes going in during this milestone. The idea is to do some exploratory testing to ensure we have not introduced new bugs by ensuring:

• you can create editor layouts and sizing works good and is preserved across reloads
• there are no exceptions in the console when working with the grid overall
• try with normal text editors, diff editors, settings editor and webview
  • side-by-side and settings editor have different size constraints, to try resizing them to their minimum sizes

2x2

The 2x2 grid is newly implemented:

• You can enable it via View > Editor Layout > Grid (2x2)
• Test that the sashes are connected
• Test that as soon as the grid structure changes, the 2x2 behaviour is dropped
• Test that everything is persisted on reload
• Test that editor minimum widths/heights are respected (eg. the settings editor has a larger minimum width/height than regular editors)

[rebornix]

It works as expected during my testing with markdown preview, zen mode, centered editors, diff view, etc. I really like it.