Updating copyright headers

Summary:
As titled. Updating copyright headers do to missing `copyright` pattern on two files:
```
COPYRIGHT_HEADERS_EXIST: Copyright Headers
****************************************
FIX IT! https://our.intern.facebook.com/intern/opensource/github/repo/219788476361611/repo_settings/header_exemptions/
Every project specific source file must contain a doc block with an appropriate copyright header. Unrelated files must be listed as exceptions in the Copyright Headers Exceptions page in the repo dashboard.
A copyright header clearly indicates that the code is owned by Facebook. Every open source file must start with a comment containing "Meta Platforms, Inc. and affiliates"
https://github.com/facebookresearch/torch_ucc/blob/main/test/torch_multiple_comms_test.py:
The first 16 lines of 'test/torch_multiple_comms_test.py' do not contain the patterns:
	Copyright
https://github.com/facebookresearch/torch_ucc/blob/main/test/torch_tests.py:
The first 16 lines of 'test/torch_tests.py' do not contain the patterns:
	Copyright
```

Differential Revision: D48912829

fbshipit-source-id: 56422e67d055ff2d6df781d3fe6807ef710d6128

test/torch_multiple_comms_test.py

@@ -1,4 +1,4 @@
-# (c) Meta Platforms, Inc. and affiliates. Confidential and proprietary.
+# Copyright (c) Meta Platforms, Inc. and affiliates. Confidential and proprietary.
 
 from torch_ucc_test_setup import *
 

test/torch_tests.py

@@ -1,4 +1,4 @@
-# (c) Meta Platforms, Inc. and affiliates. Confidential and proprietary.
+# Copyright (c) Meta Platforms, Inc. and affiliates. Confidential and proprietary.
 
 import os
 import sys