Adding unit test for checking the copyright headers and removing the check_copyright_headers in ci_tools

[srivatsankrishnan]

Summary

Added pytest for checking copyright headers and removed the ci_tools\check_copyright_headers.py as suggested by @TaekyungHeo.

Test Plan

Run the pytest

$ pytest --vv --cov

[TaekyungHeo]

Let's validate full copyright notice. Reason - In CloudAIX, we have a single-line notice.

# Copyright (c) 2024, NVIDIA CORPORATION.  All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

[srivatsankrishnan]

Looks like the vulture relies on ci_tools? @TaekyungHeo

[TaekyungHeo]

LGTM. Let's wait for @amaslenn and @srinivas212.