Fix typo in FF actor

What does this MR do and why?

Noticed this typo while enabling the FF.

In local development and tests I globally enabled so per project check and this typo was not captured.

Note: FF is already fully enabled on gitlab.com after staging and things are looking stable so far.

How to set up and validate locally

1. Create a Simple scan result policy like this example.
2. Enable the FF in rails console for the project say 12 so Feature.enable(:sync_mr_approval_rules_security_policies, Project.find(12))
3. Create a new protected branch which invokes Security::ProcessScanResultPolicyWorker and in the log/sidekiq.log, we should observe the new worker with job_status: start and job_status: done.

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 #411500 (closed)