GUIUtil::brintToFront workaround for Wayland

[pablomartin4btc]

There are known issues around handling windows focus in Wayland (this one specific in KDE but also in gnome).

The idea is that the workaround will be executed if bitcoin-qt is running using Wayland platform (e.g.: QT_QPA_PLATFORM=wayland ./src/qt/bitcoin-qt -regtest), since the workaround behaviour looks like re-opening the window again (which I tried to fix by moving the window to the original position and/ or re-setting the original geometry without success) while in X11 (not sure in Mac) the current GUIUtil::brintToFront actually sets the focus to the desired window, keeping its original position as expected, and I didn't want to change that (X11 behaviour).

The solution was initially discussed with hebasto in #817.

[DrahtBot]

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Type	Reviewers
ACK	hebasto

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Conflicts

No conflicts as of last run.

[DrahtBot]

🚧 At least one of the CI tasks failed.
_{Debug: https://github.com/bitcoin-core/gui/runs/28126764186}

Hints

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  affected test.

• An intermittent issue.

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[hebasto]

Concept ACK.

[hebasto]

ACK 15aa7d0.

Tested on Ubuntu 24.04. The behavior with QT_QPA_PLATFORM=wayland has become more consistent with the behavior with QT_QPA_PLATFORM=xcb.

Tested on macOS 12.7.6 Monterey. No behavior changes observed.