Show an alert once a protected branch is created

From #390046 (comment 1263539902)

The flow from creating a protected branch to navigate back to "Branch rules" is not smooth at the moment. Once a protected branch is created, how do I get back to "Branch rules", where is "Branch rules"? Having a link or an alert could help guide users get to branch rules from protected branches area.

We could add some text and link back to "Branch rules"

display an alert after a protected branch is created. This could happen every time a protected branch is created to bring awareness to branch rules as a centralized area to manage branch settings.

In the alert mockup, it should appear inline within the "protected branches" section and not at a top of the entire page

Availability and Testing

System spec required to verify alert functionality, this should also be incorporated in the new Branch Rules E2E (follow up Quality task created in gitlab-org/quality/quality-engineering/team-tasks#1663 (closed)).