Fix version-cal CI: correct azdev setup extension repo directory name

[Copilot]

The version-cal CI job (and related azdev-linter/azdev-style jobs) was failing because azdev setup -r azure-cli-extensions expected a checkout directory named azure-cli-extensions, but this repo (k8s-extension) checks out to k8s-extension.

Changes

• .github/workflows/VersionCalPRComment.yml: Update azdev setup -r azure-cli-extensions → azdev setup -r k8s-extension
• .github/actions/env-setup/action.yml: Same fix in the shared composite action used by AzdevLinter and AzdevStyle workflows

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This checklist is used to make sure that common guidelines for a pull request are followed.

Related command

N/A — CI workflow fix only

General Guidelines

• Have you run azdev style <YOUR_EXT> locally? (pip install azdev required)
• Have you run python scripts/ci/test_index.py -q locally? (pip install wheel==0.30.0 required)
• My extension version conforms to the Extension version schema

For new extensions:

• My extension description/summary conforms to the Extension Summary Guidelines.

About Extension Publish

There is a pipeline to automatically build, upload and publish extension wheels.
Once your pull request is merged into main branch, a new pull request will be created to update src/index.json automatically.
You only need to update the version information in file setup.py and historical information in file HISTORY.rst in your PR but do not modify src/index.json.