Fill the name, description and scopes PAT form based on parameters

What does this MR do and why?

Fill the name, description and scopes PAT form based on parameters

According to https://docs.gitlab.com/user/profile/personal_access_tokens/#prefill-personal-access-token-name-and-scopes, the personal access token (PAT) form should be pre-fillable.

References

Closes #545324 (closed)

Screenshots or screen recordings

Screen_Recording_2025-05-26_at_16.55.32

How to set up and validate locally

1. Enable this feature flag: https://gdk.test:3443/rails/features/migrate_user_access_tokens_ui
2. Go to: https://gdk.test:3443/-/user_settings/personal_access_tokens?name=My%20token&scopes=read_user,api,dummy&description=My%20description
3. It should display the form with the My token in the input name and read_user and api scopes checked.

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.