Revert "experiment(app): simulate very long enqueue operations (15s)"

This reverts commit eb6a323d0b70004732de493d6530e08eb5ca8acf.

invokeai/app/services/session_queue/session_queue_sqlite.py

@@ -2,7 +2,6 @@ import asyncio
 import json
 import sqlite3
 import threading
-from time import sleep
 from typing import Optional, Union, cast
 
 from pydantic_core import to_jsonable_python
@@ -116,8 +115,6 @@ class SqliteSessionQueue(SessionQueueBase):
             max_queue_size = self.__invoker.services.configuration.max_queue_size
             max_new_queue_items = max_queue_size - current_queue_size
 
-            sleep(15)  # Simulate a slow operation
-
             priority = 0
             if prepend:
                 priority = self._get_highest_priority(queue_id) + 1