Revert "Remove temporary VolumeSize migration logic"

This reverts commit 375ae94ce93d2323cc247a0451a4bf9e9366aeba. It causes a regression outlined in #1723.

[X] The title of this PR would make a good line in Acorn's Release Note's Changelog
[X] The title of this PR ends with a link to the main issue being address in parentheses, like: This is a title (#1216). Here's an example
[X] All relevant issues are referenced in the PR description. NOTE: don't use GitHub keywords that auto-close issues
[X] Commits follow contributing guidance
[X] Automated tests added to cover the changes. If tests couldn't be added, an explanation is provided in the Verification and Testing section
[X] Changes to user-facing functionality, API, CLI, and upgrade impacts are clearly called out in PR description
[ ] PR has at least two approvals before merging (or a reasonable exception, like it's just a docs change)

acorn-io / runtime