Use proper type for Mapped

Co-authored-by: John Davis <jdavcs@gmail.com>

lib/galaxy/model/__init__.py

@@ -2946,7 +2946,7 @@ class Notification(Base, Dictifiable, RepresentById):
     variant: Mapped[str] = mapped_column(
         String(16), index=True, nullable=True
     )  # Defines the 'importance' of the notification ('info', 'warning', 'urgent', etc.). Used for filtering, highlight rendering, etc
-    dispatched: Mapped[Boolean] = mapped_column(
+    dispatched: Mapped[bool] = mapped_column(
         Boolean, index=True, default=False
     )  # Whether the notification has been dispatched to users via other channels
     galaxy_url: Mapped[Optional[str]] = mapped_column(