move FlyteSchema deprecation warning to initialization method (#1558)

* move FlyteSchema deprecation warning to initialization method

Signed-off-by: Niels Bantilan <niels.bantilan@gmail.com>

* update

Signed-off-by: Niels Bantilan <niels.bantilan@gmail.com>

---------

Signed-off-by: Niels Bantilan <niels.bantilan@gmail.com>

flytekit/types/schema/types.py

@@ -186,7 +186,6 @@ class FlyteSchema(object):
     """
     This is the main schema class that users should use.
     """
-    logger.warning("FlyteSchema is deprecated, use Structured Dataset instead.")
 
     @classmethod
     def columns(cls) -> typing.Dict[str, typing.Type]:
@@ -203,6 +202,7 @@ def format(cls) -> SchemaFormat:
     def __class_getitem__(
         cls, columns: typing.Dict[str, typing.Type], fmt: SchemaFormat = SchemaFormat.PARQUET
     ) -> Type[FlyteSchema]:
+        logger.warning("FlyteSchema is deprecated, use Structured Dataset instead.")
         if columns is None:
             return FlyteSchema
 
@@ -240,6 +240,7 @@ def __init__(
         supported_mode: SchemaOpenMode = SchemaOpenMode.WRITE,
         downloader: typing.Optional[typing.Callable] = None,
     ):
+        logger.warning("FlyteSchema is deprecated, use Structured Dataset instead.")
         if supported_mode == SchemaOpenMode.READ and remote_path is None:
             raise ValueError("To create a FlyteSchema in read mode, remote_path is required")
         if (