Update inst-seg model export to include feature vector and saliency map

[eugene123tw]

Summary

This PR fixed explain model for MaskRCNN/RTMDet-Inst/MaskRCNN-TV instance segmentation model

• Export feature vector when explain_mode is ON
• Export dummy saliency map when explain_mode is ON (saliency map is handled in MAPI)
• Add MaskRCNN-TV explainable feature for PyTorch model

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

[sovrasov]

@eugene123tw thanks for the prompt fix! To address the issue in Geti 2.5 the changes should target OTX 2.2 release branch as well

The base branch was changed.

[harimkang]

i create PR that include same changes to 2.2 (#4056)

[sungchul2]

@eugene123tw could you describe the purpose and changes of this PR in Summary?