auto_shard_test is too slow to always finish at medium

PiperOrigin-RevId: 451470813

Author: atondwal

tensorflow/python/data/experimental/kernel_tests/service/BUILD

@@ -9,7 +9,7 @@ package(
 
 tf_py_test(
     name = "auto_shard_test",
-    size = "medium",
+    size = "large",
     srcs = ["auto_shard_test.py"],
     shard_count = 32,
     tags = [