Specifically, with the AWS credential fields:

* Replace SHOUTY CAPS with normal sentence case.

* Remove the word "ID" from the label of the second field; it's a key,
not an ID.

* Remove gratuitous snake_case from the validation messages.

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### Motivation and context
<!-- Why is this change required? What problem does it solve? If it
fixes an open
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The shouty caps were mildly irritating, and once I started fixing them,
I decided I might as well fix some other issues too.

### How has this been tested?
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Include details of your testing environment, and the tests you ran to
see how your change affects other areas of the code, etc. -->

### Checklist
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- [x] I submit my changes into the `develop` branch
- [x] I have added a description of my changes into the
[CHANGELOG](https://github.com/opencv/cvat/blob/develop/CHANGELOG.md)
file
- ~~[ ] I have updated the documentation accordingly~~
- ~~[ ] I have added tests to cover my changes~~
- ~~[ ] I have linked related issues (see [GitHub docs](

https://help.github.com/en/github/managing-your-work-on-github/linking-a-pull-request-to-an-issue#linking-a-pull-request-to-an-issue-using-a-keyword))~~
- [x] I have increased versions of npm packages if it is necessary

([cvat-canvas](https://github.com/opencv/cvat/tree/develop/cvat-canvas#versioning),

[cvat-core](https://github.com/opencv/cvat/tree/develop/cvat-core#versioning),

[cvat-data](https://github.com/opencv/cvat/tree/develop/cvat-data#versioning)
and

[cvat-ui](https://github.com/opencv/cvat/tree/develop/cvat-ui#versioning))

### License

- [x] I submit _my code changes_ under the same [MIT License](
https://github.com/opencv/cvat/blob/develop/LICENSE) that covers the
project.
  Feel free to contact the maintainers if that's a concern.

---------
Co-authored-by: NBoris Sekachev <sekachev.bs@gmail.com>