Remove unused type hint from run_alphafold script.

PiperOrigin-RevId: 454817469
Change-Id: I677ee0cabbcf64b4682a0f4b218c23daf95ac13e

run_alphafold.py

@@ -21,7 +21,7 @@ import random
 import shutil
 import sys
 import time
-from typing import Dict, Union, Optional
+from typing import Dict, Union
 
 from absl import app
 from absl import flags