[LintDiff][SDK automation] Detect the duplicated schema issue in the spec PR pipeline

Control plane SDK is generated based on a tag defined in the readme. It might include multiple swaggers within a tag. If the combination of all these referenced swaggers within a tag contain same schema name but different values, then this issue would block the SDK generation.

Is `lintDiff` tool still an extension of `autorest` or it gets rid of `autorest` dependency? If using autorest, it should be able to identify this schema duplication issue. Otherwise, can we add a check to run `autorest modeler 4` in the spec PR pipeline?