Enable license expression feature flags by default

What does this MR do and why?

Enables two EE feature flags by default:

• sync_v3_license_expressions — PackageMetadata license sync uses the v3 SPDX expression format from PDS instead of v2.

• license_expression_checker — license approval policies use LicenseExpressionChecker (understands SPDX compound expressions like MIT AND Apache-2.0) instead of DeniedLicensesChecker. Type changed from wip to beta, since wip flags cannot be default_enabled: true.

Rollout issue for license_expression_checker to follow.

References

• Sync V3 license expression ingestion (gitlab-org#22880 - closed) • Orin Naaman • 19.4
• [FF] `sync_v3_license_expressions` — roll out t... (#626708 - closed) • Orin Naaman • 19.4
• Add `LicenseExpressionChecker`: feature flag + ... (#600032 - closed) • Imam Hossain • 19.2

Screenshots or screen recordings

Not applicable — no UI change.

How to set up and validate locally

bundle exec rspec ee/spec/models/package_metadata/sync_configuration_spec.rb \
  ee/spec/workers/package_metadata/licenses_sync_worker_spec.rb \
  ee/spec/services/security/scan_result_policies/update_license_approvals_service_spec.rb

MR acceptance checklist

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