Add delay in reset_connections

Prob

On big documents (lot of children), this part can make a big amount of request in a short (instant) amount of time. Wr should add a delay in the loop:

https://github.com/suitenumerique/docs/blob/5728fcdfbc4ead2203d5dfd67af9882cbd808141/src/backend/core/services/collaboration_services.py#L41-L45