Add orgUserHasExistingUser parameters to org invite

[Timshel]

With the new web-vault web-v2024.6.2 the organization invitation logic was rewritten (had a look since organization invitation is now working even with sso :tada:).

Discovered that there were additional parameters that were not used such as orgUserHasExistingUser which allows to control if the user is redirected to the create account or login page (Cf web-v2024.6.2/accept-organization.component.ts, but this already existed before).

The additional orgSsoIdentifier parameter could then be added to the SSO PR.