Comment 3 for bug 2012077

Steps to reproduce
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1) Start the install and go all the way to the partitioning screen
2) Selected guided partitioning (erase everything) and click Next
3) On the confirmation screen, open a terminal and run this command:
    * sudo udevadm trigger
4) Upon clicking next, subiquity will hand an empty configuration to curtin - resulting in a crash later on.

Root cause analysis
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What happens is that when the user is on the desktop installer's partitioning confirmation screen, subiquity is still listening to udev events.

If it receives a udev event, subiquity triggers a new probert run, which eventually calls FilesystemModel.reset() on completion. This means already POST-ed data end up being discarded.

It only happens in the desktop installer because the server installer marks filesystem configured upon reaching the confirmation screen. This makes subiquity ignore further udev events.

I recommend we do the same for the desktop installer, although fixing the race condition entirely would be better.