chore(triggers): drop _sqlmodel_compat helper

No call-sites left after the worker and crud refactors. The previous
filter (``module=r"sqlmodel\.ext\.asyncio\.session"``) never matched
anyway: SQLModel emits the deprecation via ``typing_extensions.@deprecated``
with stacklevel=2, so the attributed module was always the caller
(our own code), not the sqlmodel module path. Removing the helper
keeps the tree honest about the fact that we no longer take the
deprecation path at all.

src/backend/base/langflow/services/triggers/_sqlmodel_compat.py

@@ -1,44 +0,0 @@
-"""Compatibility helpers around SQLModel quirks.
-
-SQLModel's ``AsyncSession.execute`` is the right choice — and the only
-choice — for ``text()`` raw SQL and for ``update()`` / ``delete()``
-constructs. The library still raises a ``DeprecationWarning`` on
-every ``execute`` call urging the caller to use ``exec`` instead, even
-when ``exec`` does not accept the statement type. The warning is
-informational and unrelated to anything actionable on our end.
-
-This module centralises a tight context manager that silences only
-that specific warning, so every trigger module can wrap its raw-SQL
-``execute`` calls without each one re-implementing the suppression.
-
-The filter is narrow on purpose: scoped to the SQLModel module path
-so any other ``DeprecationWarning`` from somewhere else still
-surfaces.
-"""
-
-from __future__ import annotations
-
-import warnings
-from contextlib import contextmanager
-from typing import TYPE_CHECKING
-
-if TYPE_CHECKING:
-    from collections.abc import Iterator
-
-
-@contextmanager
-def suppress_sqlmodel_exec_warning() -> Iterator[None]:
-    """Silence SQLModel's 'use exec()' nudge for the wrapped block.
-
-    Use around the few legitimate ``session.execute(...)`` calls we
-    have (raw SQL via :func:`sqlalchemy.text`, or ORM
-    ``update()`` / ``delete()`` constructs that :meth:`AsyncSession.exec`
-    explicitly does not accept).
-    """
-    with warnings.catch_warnings():
-        warnings.filterwarnings(
-            "ignore",
-            category=DeprecationWarning,
-            module=r"sqlmodel\.ext\.asyncio\.session",
-        )
-        yield