Pass excluded paths to SAST and DS

What does this MR do?

• Add SAST_EXCLUDED_PATHS, SAST_BANDIT_EXCLUDED_PATHS to the env vars passed to the sast job.
• Add DS_EXCLUDED_PATHS to the env vars passed to the dependency_scanning job.

Needed for https://gitlab.com/gitlab-org/gitlab-ee/issues/10030

See also https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/28018 in GitLab CE

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Performance and testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team