Add age filter for scan result policies

What does this MR do and why?

This MR adds a new age filter for scan result policies. Depends on BE: Support new Age filtering options (#399116 - closed).

Screenshots or screen recordings

age_filter

How to set up and validate locally

1. Ensure the GitLab Ultimate license is enabled
2. Navigate to a project/group => Security & Compliance => Policies => New policy => Scan result policy
3. Verify the filter is hidden
4. Choose License Scan
5. Verify the filter is hidden
6. Choose Security Scan
7. Verify the filter can be changed and the yaml is updated appropriately
8. Navigate to yaml mode, make changes to values to a value that does exist, navigate to rule mode and ensure the description has been updated
9. Create the policy, edit it, verify the description is assigned the appropriate values

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.

Related to #397086 (closed)