Add policy group scope to a drawer

What does this MR do and why?

1. Policy scope has a new feature that allows selecting groups to apply policies to, in addition to projects.
2. It is reflected now in policy list in policy scope
3. It is reflected in policy details drawer

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

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Description	UI
Drawer details and table details for groups scope	groups.mov

How to set up and validate locally

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

1. Enable feature flag:

   echo "Feature.enable(:policy_group_scope)" | rails c

2. Go to a group

3. Secure -> Policies

4. New policy => any type

5. Make sure there is an option all projects in linked groups

6. Select it, select groups exception projects -> save policy

7. Go back to list

8. Make sure you have saved policy in list and it has groups scope in scope column

9. Click on a policy row, make sure changes are reflected in policy scope section of a drawer

Related to #478426 (closed)