Duplicate imports are out of scopes as Roslyn already raises an issue in this case. As Roslyn issues are enabled by default thiswould simply create duplicates.
We are removing this rule from SonarWay due to its performance issues. After the rule gets re-designed to avoid perf issues, (see https://github.com/SonarSource/sonar-dotnet/issues/3761[#3761]), we should bring it back to SonarWay.