xdg-shell: Continue transform of popup until size fits

[DashieTM]

Describe your PR, what does it fix/add?

• applies all 3 steps of the protocol until it fits or doesn't find a suitable position
  This is before this change:

nautilus.mp4

Is there anything you want to mention? (unchecked code, possible bugs, found problems, breaking compatibility, etc.)

There is an issue with opening the popup at the exact point where it should flip upwards -> it pops up, and then flips (this also exists in main)

Is it ready for merging, or does it need work?

Should be ready other than what's above

[vaxerski]

excuse me?

[DashieTM]

But why would they put slide as 1 and 2... ffs
aight, I'm gonna find a way to make the current order work and change the title and commit after.

[DashieTM]

There we go, proper order. It just didn't apply the flip because it tested if the flip change by itself would fix the position. Hence it continued and eventually failed to position the popup.

[vaxerski]

gangsta, thanks