Remove FF resolve_vulnerability_claude_3_7_rollout

What does this MR do and why?

Issue: #523503 (closed)

This FF has been enabled globally and it's now stable where the FF can be removed.

References

Screenshots or screen recordings

Everything is still working as expected:

Resolve with AI	AI Generated MR	MR Fix

How to set up and validate locally

1. Clone this project: https://gitlab.com/gitlab-examples/wayne-enterprises/wayne-financial/cloud-native-lab
2. Run a successful pipeline
3. Go to the vulnerability report page
4. Find the vulnerability "Resolve vulnerability: Allocation of resources without limits or throttling"
5. Click on "Resolve with AI"
6. It should generate a MR that is like this one: https://gitlab.com/gitlab-examples/wayne-enterprises/wayne-financial/cloud-native-lab/-/merge_requests/18/diffs

MR acceptance checklist

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

Related to #523503 (closed)