fix: use fastuuid helper (#14903)

* fix: use fastuuid helper across the codebase

First batch of changes, simple drop in replacement.

* second batch of changes

* fixed: script mistake on helper file

tests/proxy_unit_tests/test_custom_callback_input.py

@@ -6,7 +6,7 @@ import os
 import sys
 import time
 import traceback
-import uuid
+from litellm._uuid import uuid
 from datetime import datetime
 
 import pytest