Revert "Increase the number of unique bits for actors to avoid handle collisions (#12894)" (#12988)

This reverts commit 3e492a79ec.

python/ray/utils.py

@@ -50,9 +50,9 @@ def get_ray_temp_dir():
 
 
 def _random_string():
-    id_hash = hashlib.shake_128()
+    id_hash = hashlib.sha1()
     id_hash.update(uuid.uuid4().bytes)
-    id_bytes = id_hash.digest(ray_constants.ID_SIZE)
+    id_bytes = id_hash.digest()
     assert len(id_bytes) == ray_constants.ID_SIZE
     return id_bytes