Fix Qt 6.7 QML engine segfault

[kairosci]

This pull request fixes the failing QML format job by adding a command fallback since the binary location changed on Arch Linux. It also updates the flatpak external data checker configuration for libebur128 to use git tags in order to avoid GitHub API rate limits that were causing the Flatpak lint job to fail.

Crucially, it also resolves the root cause of the segmentation fault tracked in #5120. In Qt 6.7, a known issue causes the QML engine to occasionally segfault when initializing components if Javascript array syntax ([]) is used to assign to QML list properties like actions. Because actions is the default property of Kirigami.ActionToolBar, we can safely omit the actions: [] wrapper. This removes the array conversion, completely fixing the random runtime segfaults.

Closes #5120

[github-actions]

Workflow failed, but the following artifacts are still available for this pull request:

• easyeffects-flatpak-merge-f39d79785-into-0e303ce3e-x86_64.flatpak.zip
• easyeffects-archlinux-merge-f39d79785-into-0e303ce3e-x86_64.zip
• easyeffects-flatpak-merge-f39d79785-into-0e303ce3e-aarch64.flatpak.zip

[wwmm]

Crucially, it also resolves the root cause of the segmentation fault tracked in #5120. In Qt 6.7, a known issue causes the QML engine to occasionally segfault when initializing components if Javascript array syntax ([]) is used to assign to QML list properties like actions

Although I am not a fan of the proposed syntax using it isn't the end of the world. But I wonder if that is actually the fix for #5120. At least in our latest flatpak package release Qt 6.7 is not used. It uses 6.10.3.

[wwmm]

And it seems qt 6.7 has already reached end of life. Are there still many distributions using it when compiling easyeffects native packages? As users on older system usually use our Flatpak package I prefer to write the source code targeting more recent library versions.