refactor(migration/model): update column types for workflow schema (#10160)

api/migrations/versions/2024_11_01_0623-09a8d1878d9b_update_workflows_graph_features_and_.py

                nullable=False)
         batch_op.alter_column('features',
                existing_type=sa.TEXT(),
-               type_=sa.String(),
                nullable=False)
         batch_op.alter_column('updated_at',
                existing_type=postgresql.TIMESTAMP(),
                existing_type=postgresql.TIMESTAMP(),
                nullable=True)
         batch_op.alter_column('features',
-               existing_type=sa.String(),
-               type_=sa.TEXT(),
+               existing_type=sa.TEXT(),
                nullable=True)
         batch_op.alter_column('graph',
                existing_type=sa.TEXT(),

api/models/workflow.py

 from enum import Enum
 from typing import Any, Optional, Union
 
+import sqlalchemy as sa
 from sqlalchemy import func
 from sqlalchemy.orm import Mapped, mapped_column
 
     app_id: Mapped[str] = mapped_column(StringUUID, nullable=False)
     type: Mapped[str] = mapped_column(db.String(255), nullable=False)
     version: Mapped[str] = mapped_column(db.String(255), nullable=False)
-    graph: Mapped[str] = mapped_column(db.Text)
-    _features: Mapped[str] = mapped_column("features")
+    graph: Mapped[str] = mapped_column(sa.Text)
+    _features: Mapped[str] = mapped_column("features", sa.TEXT)
     created_by: Mapped[str] = mapped_column(StringUUID, nullable=False)
     created_at: Mapped[datetime] = mapped_column(
         db.DateTime, nullable=False, server_default=db.text("CURRENT_TIMESTAMP(0)")