Pad tile to image size (512 x 512)

[eugene123tw]

Summary

Revert changes in this PR: https://github.com/openvinotoolkit/training_extensions/pull/3844/files
and align with pad to image size instead

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

[yunchu]

@eugene123tw @sovrasov @harimkang please don't forget to add your changes to the CHANGELOG.md
if you missed it, we need to create another PR to update that.