Undo history state problems

[mitxela]

Run the plugin and then hit edit > undo. The expected behaviour is that the board reverts to before the plugin was run.

In KiCad 6 you have to undo twice, and an error appears showing "Incomplete undo/redo operation: some items not found"

For the native arc mode, this fails to revert correctly and the tracks exist in some kind of out-of-sync limbo, and running the plugin again results in nonsense. For the subdivision method, despite the warning message, the board appears to be reverted correctly.

This seems like a KiCad glitch, but there may be some change we can make to the python to avoid it. The plugin, especially the only-selection stuff, would be much more useful if we could rely on the undo history to work.

[mitxela]

This was part of the same issue as the segfault on close, fixed as of KiCad 6.0.4 - https://gitlab.com/kicad/code/kicad/-/merge_requests/1136