Add external name field to external controls UI

What does this MR do and why?

We've introduced the concept of an external_control_name on external controls, this allows creating/updating the new external name field via the UI.

Screenshots

How to set up and validate locally

1. Navigate to the Compliance Center Dashboard, and click on frameworks i.e. http://gitlab.localdev:3000/gitlab-org/gitlab-test/-/security/compliance_dashboard/frameworks
2. In the top right, click on the "New framework" button
3. Click on "Create blank framework"
4. Fill in the framework details, make sure to fill in name, description and color
5. Then expand "Requirements", and click on "New requirement"
6. Fill in a name and a description, then click on "Add an external control"
7. Fill in "External Control Name", "External URL", "HMAC shared secret"
8. Click "Create requirement"
9. Click "Create framework"
10. On the success screen click "Edit framework"
11. Expand "Requirements", click on the three dots next to your newly created requirement and click "Edit"
12. Underneath "Controls (optional)" click the pen icon
13. You will see the External Control Name you saved earlier, updated this to a new name, fill in the HMAC secret and click "Save changes to the framework"
14. The External Control Name will now be updated

Related to #527007 (closed)