Add registration token reset in registration modal

What does this MR do and why?

This change allows users that are still using the legacy runner registration process to reset (rotate) their registration token in the modal with the registration instructions.

Screenshots or screen recordings

How to set up and validate locally

For Instance Tokens

1. Enable the feature flag: in your console rails c, and then Feature.enable(:create_runner_workflow_for_admin)
2. Visit Admin > CI/CD > Runners
3. Select New instance runner
4. Select "Prefer to use a registration token to create a runner?"
5. In the modal, select Reset registration token

For Group Tokens

1. Enable the feature flag: in your console rails c, and then Feature.enable(:create_runner_workflow_for_namespace)
2. Visit a group that you own
3. Visit Your group > CI/CD > Runners
4. Select New group runner
5. Select "Prefer to use a registration token to create a runner?"
6. In the modal, select Reset registration token

For Project Tokens

1. Enable the feature flag: in your console rails c, and then Feature.enable(:create_runner_workflow_for_namespace)
2. Visit a project you maintain
3. Select Settings > CI/CD in the menu to visit e.g. http://gdk.test:3000/flightjs/Flight/-/settings/ci_cd
4. Expand Runners
5. Select New project runner
6. Select "Prefer to use a registration token to create a runner?"
7. In the modal, select Reset registration token

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 #407365 (closed)