Fixes user-namespace for kustomize 5

[alekseyolg]

While the command is running:

kustomize build common/user-namespace/base

A warning appeared:

# Warning: 'vars' is deprecated. Please use 'replacements' instead. [EXPERIMENTAL] Run 'kustomize edit fix' to update your Kustomization automatically.

I used the command:

kustomize edit fix --vars

And also corrected errors received when executing this command. Manifests are now generated without warnings.

Please note that this PR should not affect the manifests themselves in any way, only the warning is removed.

Resolves #

Description of your changes:

Checklist:

• Unit tests pass:
  Make sure you have installed kustomize == 3.2.1
  1. make generate-changed-only
  2. make test

[juliusvonkohout]

kustomize build produces the exact same output files for this directory after the changes and i also ran a full build of example.yaml

/lgtm
/approve

[google-oss-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: alekseyolg, juliusvonkohout

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