Fix vm rows reactivity (backport #1262)

[mergify]

Summary

PR Checklist

• Is this a multi-tenancy feature/bug?
  • Yes, the relevant RBAC changes are at:
• Do we need to backport changes to the old Rancher UI, such as RKE1?
  • Yes, the relevant PR is at:
• Are backend engineers aware of UI changes?
  • Yes, the backend owner is:

Related Issue harvester/harvester#7082

Occurred changes and/or fixed issues

Technical notes summary

• VMs are now computed values
• Removing vmi mapping - vmi is already a vm's model property

Areas or cases that should be tested

Areas which could experience regressions

Screenshot/Video

Screencast.from.2025-01-09.11-50-09.webm

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This is an automatic backport of pull request #1262 done by [Mergify](https://mergify.com).