fix: e2e test case for multiple fs-backup ns mapping

[priyansh17]

In Init(), on kind, kibishiiData is intentionally zeroed out (Levels: 0, DirsPerLevel: 0, ...) because kind doesn't support volume snapshots or fs-backup ; volumes aren't backed up (--snapshot-volumes=false without --default-volumes-to-fs-backup). However, CreateResources() and Verify() unconditionally override kibishiiData.Levels to len(*n.NSIncluded) + index, which for the Multiple test sets Levels to 2 and 3. This causes generate.sh to write data into PVCs that never gets backed up, and then verify.sh fails post-restore because the data isn't there.

Fix: Guard the Levels override so it's only applied on non-kind environments where volume data is actually backed up and restored.

Failure logs: https://github.com/vmware-tanzu/velero/actions/runs/23600057117/job/68728032211#logs

Fixes #(issue)
none, e2e test case.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 59.83%. Comparing base (d8ab30c) to head (bc2e6df).

Additional details and impacted files

@@               Coverage Diff                @@
##           release-1.16    #9660      +/-   ##
================================================
- Coverage         59.84%   59.83%   -0.02%     
================================================
  Files               370      370              
  Lines             32034    32034              
================================================
- Hits              19172    19166       -6     
- Misses            11362    11367       +5     
- Partials           1500     1501       +1     

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[kaovilai]

what about other branches?

[blackpiglet]

There was no difference for this case between the release-1.16 and the main branch.
I didn't understand why this case could pass on the main branch.

I suggest to skip this case in release-1.16 instead of modifying the case logic.

[kaovilai]

whoops

[blackpiglet]

@priyansh17
Another thing worth noticing is that don't use Restic in the code change anymore.
Although there are still some codes that use Restic, that's the legacy code without refactoring.
We are officially deprecated Restic from Velero in release-1.19.
As a result, it's better to use fs-backup to replace Restic.