Add support for group level scan_result_policies

What does this MR do and why?

Related issue: #367718 (closed) #367716 (closed)

Add support for group level scan result policies.

backend :

1. Update scan result policy resolver with new relationship argument and new source field.
2. Expand scan result policy resolver to support namespace in addition to project.

frontend :

1. Add graphql query file for group level scan result policies reusing existing fragment security policy source.
2. Update security orchestration list policy to include group level scan result policies.
3. Update policy details (used under project settings > merge request approvals) to support both project and group level (inherited) scan result policies.

Screenshots or screen recordings

Project and Group level policies

Group level policies

Project settings

Merge request

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.