community: make AthenaLoader profile_name optional and fix type hint (#24958)

- **Description:** This PR makes the AthenaLoader profile_name optional
and fixes the type hint which says the type is `str` but it should be
`str` or `None` as None is handled in the loader init. This is a minor
problem but it just confused me when I was using the Athena Loader to
why we had to use a Profile, as I want that for local but not
production.
- **Issue:** #24957 
- **Dependencies:** None.

libs/community/langchain_community/document_loaders/athena.py

@@ -35,15 +35,16 @@ class AthenaLoader(BaseLoader):
         query: str,
         database: str,
         s3_output_uri: str,
-        profile_name: str,
+        profile_name: Optional[str] = None,
         metadata_columns: Optional[List[str]] = None,
     ):
         """Initialize Athena document loader.
 
         Args:
             query: The query to run in Athena.
-            database: Athena database
-            s3_output_uri: Athena output path
+            database: Athena database.
+            s3_output_uri: Athena output path.
+            profile_name: Optional. AWS credential profile, if profiles are being used.
             metadata_columns: Optional. Columns written to Document `metadata`.
         """
         self.query = query