fix(upgrade): clean up image with crictl

[starbops]

IMPORTANT: Please do not create a Pull Request without creating an issue first.

Problem:

We used ctr to remove container images initially. But that's not thorough.

Solution:

Replace the use of ctr i rm with crictl rmi.

Related Issue:

#6691

Test plan:

1. Prepare a Harvester cluster in v1.4.0
2. Prepare a customized build of Harvester ISO image containing this fix
3. Get the before-upgrade image list on each node with crictl images
4. Upgrade the cluster with the ISO image
5. After the upgrade succeed, collect the after-upgrade image list on each node
6. Besides, the result of crictl images should not contain bunch of <none> lines (please refer to [BUG] Image lists looks weird after upgrade purging images #6691 (comment) for example)
7. Compare the two lists. Images exist in v1.4.0 but not in the customized build should be removed.