Migrated `SelectField` AntD tests to @testing-library/react

[kestarumper]

I've encountered a lot of problems. Many related to fireEvent.change not working at all. AntD seems to be doing things differently when it comes to the role etc. It also does some virtualization which makes things harder.

Notes

• Some elements only appear in the DOM when you "click" on the combobox
  • ...but you can't use fireEvent.click, it has to be fireEvent.mouseDown (see references)

Reference

• https://ant.design/docs/blog/testing-migrate
• https://github.com/ant-design/ant-design/issues/23009#issuecomment-610919534
• https://github.com/ant-design/ant-design/issues/22074#issuecomment-603735566

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 87.50000% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 94.61%. Comparing base (9dec81c) to head (e2aa01a).

Files	Patch %	Lines
packages/uniforms-antd/src/SelectField.tsx	87.50%	0 Missing and 1 partial :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## select-field-tests #1312 +/- ## =================================================== Coverage 94.60% 94.61% =================================================== Files 231 231 Lines 3821 3823 +2 Branches 1029 1030 +1 =================================================== + Hits 3615 3617 +2 Misses 82 82 Partials 124 124 ```

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