Overrides SAST_EXCLUDED_ANALYZERS where necessary

What does this MR do?

As part of gitlab-org/gitlab#290777 (closed), move away from SAST_DEFAULT_ANALYZERS and utilize SAST_EXCLUDED_ANALYZERS.

We need to override SAST_EXCLUDED_ANALYZERS for some of the downstream pipelines.

This MR fixes some of the failing jobs in this pipeline: https://gitlab.com/gitlab-org/security-products/analyzers/semgrep/-/pipelines/322338636

What are the relevant issue numbers?

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 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