Fix F1 auto-threshold to choose best largest confidence

[goodsong81]

Summary

• Current adaptive threshold logic chooses the best "smallest" confidence, which might result in too small threshold, thus high level of false alarm ratio.
• Result-based threshold: before: 0.025 -> after fix: 0.425
  

How to test

• Unit test adjusted for this edge case

Checklist

• I have added unit tests to cover my changes.​
• I have added integration tests to cover my changes.​
• I have added e2e tests for validation.
• 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) 2023 Intel Corporation
# SPDX-License-Identifier: Apache-2.0

[goodsong81]

@sungmanc Could you check if this change could affect the small + low-positive scenario?

[sungmanc]

@sungmanc Could you check if this change could affect the small + low-positive scenario?

Sure, I'll check with some datasets

[goodsong81]

Retarget to develop: #2371