Add feature flag to blocking password auth for saml users method

Add possibility to readd saml user to the group

Fix unneeded change"

Change Let_it_be to let to avoid specs failure

Add spec coverage for omniauth flow

Add specs for group saml user

Fix specs file in user

Add logging out after leaving group by provisioned by this group member

Add log out after disconnecting saml

Rename method for more clarity

Changelog: added