Adding disable sign out field to SAMLP connection options

[willvedd]

Description

As noted in this Terraform provider issue, the disableSignout field is absent from SAMLP connection options, but is very much a real configuration. This PR adds this field in to then enable for the Terraform provider.

References

Original issue

Testing

• This change adds test coverage for new/changed/fixed functionality

Checklist

• I have read and agreed to the terms within the Auth0 Code of Conduct.
• I have read the Auth0 General Contribution Guidelines.
• I have reviewed my own code beforehand.
• I have added documentation for new/changed functionality in this PR.
• All active GitHub checks for tests, formatting, and security are passing.
• The correct base branch is being used, if not main.