Handle 409 conflict errors with its own exception class

[DavidMealha-Onfido]

Changes

This Pull Request doesn't change any endpoints, but does change the way the HTTP 409 error is handled by having its own exception class, this way it's easier to filter these errors on client integrations. Right now it's wrapped under the Auth0::Unsupported exception which can include multiple errors.

Given this may impact existing integration this should be a major version.

References

Testing

Please describe how this can be tested by reviewers. Be specific about anything not tested and reasons why. If this library has unit and/or integration testing, tests should be added for new functionality and existing tests should complete without errors.

• This change adds unit test coverage
• This change adds integration test coverage
• This change has been tested on the latest version of Ruby

Checklist

• I have read the Auth0 general contribution guidelines
• I have read the Auth0 Code of Conduct
• All existing and new tests complete without errors
• Rubocop passes on all added/modified files
• All active GitHub checks have passed

[DavidMealha-Onfido]

Hello @arpit-jn @gyaneshgouraw-okta, could you have a look at this MR since you seem the most recent contributors to ruby-auth0? Thanks