Add check for ref to deployment notifications

What does this MR do and why?

It adds a check for deployment notifications to make sure a notification should be send based on the setting Branches to be notified.

As mentioned in the related issue the deployment notifications were send on every branch.

Screenshots or screen recordings

How to set up and validate locally

1. Enable the feature flag

   Feature.enable(:chat_notification_deployment_protected_branch_filter)

2. Configure a Slack notifications integration and set the branches to be notified.
3. Perform a deployment on a notified branch
4. Perform a deployment on an ignored branch

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.

Closes #217020 (closed)