[PLT-1489] Removed get stream and corresponding classes (#1839)

Author: Gabefire

libs/labelbox/src/labelbox/__init__.py

@@ -25,10 +25,6 @@
 from labelbox.schema.export_task import (
     StreamType,
     ExportTask,
-    JsonConverter,
-    JsonConverterOutput,
-    FileConverter,
-    FileConverterOutput,
     BufferedJsonConverterOutput,
 )
 from labelbox.schema.labeling_frontend import (