Put publisher typevar specification back in

safir/src/safir/metrics/_event_manager.py

@@ -469,7 +469,7 @@ async def build_publisher_for_model(
         schema_info = await self._schema_manager.register_model(model)
 
         # Return the corresponding event publisher.
-        return KafkaEventPublisher(
+        return KafkaEventPublisher[P](
             application=self._application,
             event_class=model,
             publisher=async_publisher,
@@ -586,7 +586,7 @@ async def build_publisher_for_model(
         EventPublisher
             An appropriate event publisher implementation instance.
         """
-        return NoopEventPublisher(self._application, model, self.logger)
+        return NoopEventPublisher[P](self._application, model, self.logger)
 
 
 class MockEventManager(EventManager):
@@ -636,4 +636,4 @@ async def build_publisher_for_model(
         EventPublisher
             An appropriate event publisher implementation instance.
         """
-        return MockEventPublisher(self._application, model, self.logger)
+        return MockEventPublisher[P](self._application, model, self.logger)