Images on ZFS consuming more space on newer systems

[IanCollins]

A bit of a strange one and I'm unable to isolate the cause.

All systems are Ubuntu 22.04 VMs.

On older systems, I see the space used on the /var/lib/docker filesystem lower than the space reported for images with docker system df. This is expected due to filesystem compression.

For example, older system:
`$ uname -r && docker --version && zfs --version

5.15.0-105-generic

Docker version 20.10.6, build 370c289

zfs-2.1.5-1ubuntu6~22.04.4

$ zfs list mnt/docker -H -o used && zfs get compressratio mnt/docker -H -o value && docker system df|grep Ima|awk '{print $4}'

78.8G

1.75x

120.8GB`

Compared to the newer ones, where this is reversed:
`5.15.0-46-generic

Docker version 26.1.4, build 5650f9b

zfs-2.1.5-1ubuntu6~22.04.4

zfs-kmod-2.1.4-0ubuntu0.1

126G

1.73x

110.4GB`

Older docker, newer kernel:
`6.5.0-35-generic

Docker version 20.10.6, build 370c289

zfs-2.1.5-1ubuntu6~22.04.4

zfs-kmod-2.2.0-0ubuntu1~23.10.2

111G

1.49x

86.66GB`

It looks like systems with the newer docker or older docker and the 6.5.0 use more space than they should.