Modifications to support VKS environment

[blackpiglet]

Thank you for contributing to Velero!

Please add a summary of your change

• Fix the KIBISHII_DIRECTORY parameter not work for make test-e2e issue.
• Make changes to support the VKS environment. FYI, the TKGm environment support is deprecated.
• Refactor the code to get the plugin images for migration cases.

Does your change fix a particular issue?

Fixes #(issue)

Please indicate you've done the following:

• [x] Accepted the DCO. Commits without the DCO will delay acceptance.
• [ ] Created a changelog file (make new-changelog) or comment /kind changelog-not-required on this PR.
• [ ] Updated the corresponding documentation in site/content/docs/main.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 58.97%. Comparing base (ebbeb7a) to head (29d84fe). Report is 8 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #8315 +/- ## ========================================== - Coverage 58.99% 58.97% -0.02% ========================================== Files 367 367 Lines 38847 38876 +29 ========================================== + Hits 22918 22928 +10 - Misses 14467 14486 +19 Partials 1462 1462 ```

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