erp5_core: Only search for ERP5 Login
The implementation only works with ERP5 Login, since it is the only portal type that holds password in ERP5. Other implementations are password-less: Certificate Login, Google Login and Facebook Login, so they cannot have their password reset anyway.
It is overkill split the login on multiple categorization, to use some portal group (ie: getPortalLoginPortalTypeThatCanResetPassord...) until we have a a clear usecase.