Reenable e2e classification XAI tests

[GalyaZalesskaya]

Summary

Reenable e2e classification XAI tests that were disabled by mistake:

pytest /home/gzalessk/code/training_extensions/tests/e2e/cli/test_cli.py::test_otx_explain_e2e_cli --task=CLASSIFICATION
================================================== 15 passed, 1 skipped, 39 warnings in 39.89s ===================================================

How to test

Checklist

• I have added unit tests to cover my changes.​
• I have added integration tests to cover my changes.​
• I have ran e2e tests and there is no issues.
• I have added the description of my changes into CHANGELOG in my target branch (e.g., CHANGELOG in develop).​
• I have updated the documentation in my target branch accordingly (e.g., documentation in develop).
• I have linked related issues.

License

• I submit my code changes under the same Apache License that covers the project.
  Feel free to contact the maintainers if that's a concern.
• I have updated the license header for each file (see an example below).

# Copyright (C) 2024 Intel Corporation
# SPDX-License-Identifier: Apache-2.0

[GalyaZalesskaya]

@chuneuny-emily Can you please review?