community: Add support for clob datatype in oracle database (#27330)

**Description**:
This PR add support of clob/blob data type for oracle document loader,
clob/blob can only be read by oracledb package when connection is open,
so reformat code to process data before connection closes.

**Dependencies**:
oracledb package same as before. pip install oracledb

Co-authored-by: Erick Friis <erick@langchain.dev>

libs/community/langchain_community/document_loaders/oracleadb_loader.py

@@ -100,7 +100,13 @@ class OracleAutonomousDatabaseLoader(BaseLoader):
             cursor.execute(self.query)
             columns = [col[0] for col in cursor.description]
             data = cursor.fetchall()
-            data = [dict(zip(columns, row)) for row in data]
+            data = [
+                {
+                    i: (j if not isinstance(j, oracledb.LOB) else j.read())
+                    for i, j in zip(columns, row)
+                }
+                for row in data
+            ]
         except oracledb.DatabaseError as e:
             print("Got error while connecting: " + str(e))  # noqa: T201
             data = []