Remove stale checkout workaround comments

[AkashKumar7902]

Summary

• remove the obsolete Add option to fetch tags even if fetch-depth > 0 actions/checkout#579 workaround comment from reusable policy release workflows
• keep fetch-depth: 0 because the version calculation still uses git describe for tag and branch builds
• apply the same cleanup to normal policy workflows and the Rego workflow used by monorepo policies

Fixes #163

Testing

• yq e . .github/workflows/reusable-release-policy-{assemblyscript,go,go-wasi,rego,rust,swift}.yml
• git diff --check
• verified no stale checkout#579 comments remain
• verified first release checkout in each touched workflow still has fetch-depth: 0

[AkashKumar7902]

Thanks, addressed in d2c53fe. I added the full-depth checkout configuration with across the reusable policy release workflows.

[AkashKumar7902]

Follow-up: amended and pushed 3403a8d with DCO signoff. The checkout changes now include fetch-depth: 0 and persist-credentials: false across the reusable policy release workflows.