fix(aws_dms): make boto3 import lazy so other components can load without it

The lazy-loader in dagster_community_components/__init__.py imports every
component's module when dg discovers plugins — if aws_dms fails to import
because boto3 isn't installed, the whole discovery fails and every unrelated
component breaks. Guard the boto3/botocore imports so aws_dms module loads
cleanly; the actual client construction (which does need boto3) happens
inside methods and raises with a clear message if it's missing.

Surfaced by the qlik_replicate demo — dg check failed on ModuleNotFoundError
for boto3 during plugin discovery even though the demo doesn't use aws_dms.

Author: eric-thomas-dagster

integrations/aws_dms/component.py

@@ -10,8 +10,12 @@
 from typing import Optional, List, Dict, Any
 from datetime import datetime, timedelta
 
-import boto3
-from botocore.exceptions import ClientError
+try:
+    import boto3
+    from botocore.exceptions import ClientError
+except ImportError:
+    boto3 = None  # type: ignore[assignment]
+    ClientError = Exception  # type: ignore[assignment,misc]
 
 from dagster import (
     Component,