Export static shape for detection/instance-segmentation models

Summary

Fix ONNX inference issue by using static shape for detection/inst-seg models.

How to test

Added test_onnx_export unittest.

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

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 80.40%. Comparing base (31823cd) to head (efa83c3). Report is 38 commits behind head on develop.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #4113 +/- ## =========================================== + Coverage 77.11% 80.40% +3.28% =========================================== Files 308 319 +11 Lines 30571 31645 +1074 =========================================== + Hits 23576 25445 +1869 + Misses 6995 6200 -795 ``` | [Flag](https://app.codecov.io/gh/openvinotoolkit/training_extensions/pull/4113/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=openvinotoolkit) | Coverage Δ | | |---|---|---| | [py310](https://app.codecov.io/gh/openvinotoolkit/training_extensions/pull/4113/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=openvinotoolkit) | `?` | | | [py311](https://app.codecov.io/gh/openvinotoolkit/training_extensions/pull/4113/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=openvinotoolkit) | `80.40% <ø> (+3.36%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=openvinotoolkit#carryforward-flags-in-the-pull-request-comment) to find out more.

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

openvinotoolkit / training_extensions