fsck integration is not flicker free

Install Ubuntu desktop, with full disk LUKS encryption, on an UEFI system.

On boot, ESP & rootfs will have fsck started.

This flickers briefly that fsck are in progress, although most of the time both the ESP and rootfs fsck finish/exit instantly.

It would be nice delaying to show fsck progress in plymouth until it takes a substantial amount of time and/or if there is progress about it.

I.e. ideally it should not be shown if it takes less than a second to complete (or some other very quick threshold). As there is not enough to time to show the message that the fsck is in progress, for the human to read it, before the message is dissmissed again.

One can see this as a flickerfree boot effort.