Fix deprecation warning in importUserJobs

[JCQuintas]

Changes

The importUsers deprecation warning shows up even when using the suggested importUsersJob, this MR fixes that by moving importUsers logic into _importUsers. Then only when the deprecated function is called we display the warning.

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.

• management.jobs.importUsersJob should not display a warning
• management.jobs.importUsers should display a warning
• Existing tests still run

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

[frederikprijck]

Thanks for the PR @JCQuintas , that's a nice catch, very much appreciated!