refactor: Use typed SQLAlchemy base model and fix type errors (#19980)

Signed-off-by: -LAN- <laipz8200@outlook.com>

api/models/tools.py

@@ -172,10 +172,6 @@ class WorkflowToolProvider(Base):
         db.DateTime, nullable=False, server_default=db.text("CURRENT_TIMESTAMP(0)")
     )
 
-    @property
-    def schema_type(self) -> ApiProviderSchemaType:
-        return ApiProviderSchemaType.value_of(self.schema_type_str)
-
     @property
     def user(self) -> Account | None:
         return db.session.query(Account).filter(Account.id == self.user_id).first()