Bump github.com/Azure/terraform-module-test-helper in /test (#122)

Bumps [github.com/Azure/terraform-module-test-helper](https://github.com/Azure/terraform-module-test-helper) from 0.16.0 to 0.26.0.
- [Commits](Azure/terraform-module-test-helper@v0.16.0...v0.26.0)

---
updated-dependencies:
- dependency-name: github.com/Azure/terraform-module-test-helper
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>