Increase groupsselect limit

What does this MR do?

Sets the GroupsSelect dropdown per_page limit to 100 instead of 20.

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

Is 100 a good new limit? This is only a temp fix, the core issue is that the user is searching AA but group AA is not returned as the most relevant result.

Why was this MR needed?

customer+ and customer.

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated
• API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Contributes to #20013 (closed)