Consider using infinite queries for UI dropdown content

[Etsija]

Currently, these dropdowns which are populated from API endpoints use ALL_ITEMS for fetching:

• organization dropdowns in admin/users/create-user, admin/plugins/..., move-repository, siblings
• product/repository sibling dropdowns in move-repository, siblings

It should be investigated, whether fetching ALL_ITEMS in these dropdowns could be replaced with async searchable / infinite dropdowns, using this concept from TanStack Query: https://tanstack.com/query/v5/docs/framework/react/guides/infinite-queries