Transfer project to group API should have same permissions as in the UI

Description

Transfer project to group API is currently only available for "admin" user. This API should be available for non-admin users as well because in the UI, non-admin users do have permission to transfer projects.

Proposal

Make Transfer project to group API available to non-admin users.

Links / references

Feature checklist

Make sure these are completed before closing the issue, with a link to the relevant commit.