Authorizations regarding OAuth - style confirmation

What does this MR do?

Changed the styling of OAuth authorization page in order to follow the styling structure described in #28849 (closed).

Are there points in the code the reviewer needs to double check?

No

Why was this MR needed?

For #35721 (closed)

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
  • Has been reviewed by Backend
  • Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together

What are the relevant issue numbers?

Closes #35721 (closed)