Add a regression guard to validate-renovate-container-image.sh that
exercises a mise shim and detects the argv[0]-drop wrapper bug
introduced by containerbase's install-tool mise.

This commit is intentionally added BEFORE the fix so the pipeline
demonstrates the bug visibly. The next commit (the revert of 1a395c49)
makes the test pass.

AI-assisted: OpenCode (claude-opus-4-7)

This reverts commit 1a395c49.

Revert "chore: install mise via install-tool in Renovate image"

See merge request !1475

## [3.24.3](https://gitlab.com/gitlab-com/gl-infra/common-ci-tasks/-/compare/...) (2026-05-05)

### Reverts

* Revert "chore: install mise via install-tool in Renovate image" ([ee68ce85](ee68ce85))

### Tests

* **renovate:** assert mise shims dispatch correctly ([b20e7793](b20e7793))