Override custom sast rules if SECURE_ENABLE_LOCAL_CONFIGURATION is false

What does this MR do?

The ruleset module will override default or remote ruleset only if SECURE_ENABLE_LOCAL_CONFIGURATION is set true \

See gitlab repo MR for changes in UI

What are the relevant issue numbers?

Disallow project-level SAST/SD/IaC overrides when a configuration is specified at the group level in a Scan Execution Policy

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated for GitLab EE, if necessary
• Documentation created/updated for this project, if necessary
• Documentation reviewed by technical writer or follow-up review issue created
• Tests updated/added for this feature/bug
• Job definition updated, if necessary
  • Auto-DevOps template
  • Job definition example
  • CI Templates
• Conforms to the code review guidelines
• Conforms to the Go guidelines
• Security reports checked/validated by reviewer