[Feature] Sharing with external email ( not federated ) #1703

Steps to reproduce

1. type an email address with a domain not federated like user@gmail.com

Expected behaviour

User expect that a custom share link would be generated and sent to this email, later on , the share could be deactivated so this link would not work anymore.

Actual behaviour

Error is returned : federated domain cannot be reach

Server configuration

Operating system: Any

Web server: Any

Database: Any

PHP version: Any

Nextcloud version: 10.0.1

Updated from an older Nextcloud/ownCloud or fresh install: NO

Where did you install Nextcloud from: zip file

**Are you using external storage : NO

Are you using encryption: yes/no

**Are you using an external user-backend, : NO

Already discussed here :

owncloud/core#20074