feat(events): add dynamic invocation & result validators

This is required to get these event fields to deserialize correctly. If omitted, pydantic uses `BaseInvocation`/`BaseInvocationOutput`, which is not correct.

This is similar to the workaround in the `Graph` and `GraphExecutionState` classes where we need to fanagle pydantic with manual validation handling.

invokeai/app/services/events/events_common.py

@@ -3,7 +3,7 @@
 
 from fastapi_events.handlers.local import local_handler
 from fastapi_events.registry.payload_schema import registry as payload_schema
-from pydantic import BaseModel, ConfigDict, Field, SerializeAsAny
+from pydantic import BaseModel, ConfigDict, Field, SerializeAsAny, field_validator
 
 from invokeai.app.invocations.baseinvocation import BaseInvocation, BaseInvocationOutput
 from invokeai.app.services.session_processor.session_processor_common import ProgressImage
@@ -101,6 +101,14 @@ class InvocationEventBase(QueueItemEventBase):
     invocation: SerializeAsAny[BaseInvocation] = Field(description="The ID of the invocation")
     invocation_source_id: str = Field(description="The ID of the prepared invocation's source node")
 
+    @field_validator("invocation", mode="plain")
+    @classmethod
+    def validate_invocation(cls, v: Any):
+        """Validates the invocation using the dynamic type adapter."""
+
+        invocation = BaseInvocation.get_typeadapter().validate_python(v)
+        return invocation
+
 
 @payload_schema.register
 class InvocationStartedEvent(InvocationEventBase):
@@ -176,6 +184,14 @@ class InvocationCompleteEvent(InvocationEventBase):
 
     result: SerializeAsAny[BaseInvocationOutput] = Field(description="The result of the invocation")
 
+    @field_validator("result", mode="plain")
+    @classmethod
+    def validate_results(cls, v: Any):
+        """Validates the invocation result using the dynamic type adapter."""
+
+        result = BaseInvocationOutput.get_typeadapter().validate_python(v)
+        return result
+
     @classmethod
     def build(
         cls, queue_item: SessionQueueItem, invocation: BaseInvocation, result: BaseInvocationOutput