Use MergeRequests::V2ApprovalRules::DestroyService for DELETE requests when v2 feature flag is enabled. Requirements: - Update EE::API::MergeRequestApprovalRules DELETE endpoint to check use_v2_approval_rules? flag - Call v2 DestroyService when enabled, v1 service when disabled - Add API request specs testing successful deletion, authorization failures, 404 errors, and feature flag toggle - Ensure response format matches v1 Reference: v2 Approval Rules POC (https://gitlab.com/gitlab-org/gitlab/-/merge_requests/222865)