Disable unit tests for flakyness in CircleCI (#45133)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/45133

Recently, CircleCI has failed pretty often due to these tests.
The reason is that we migrated these jobs to M1 machines, as circleCI is deprecating intel ones, and on these machines the simulators tend to freeze. Hence, every often we get stuck when running the tests. :(

We are going to move to GHA, so that should not be a big issue.

## Changelog:
[Internal] - Disable unit tests in CircleCI to improve CI robustness

Reviewed By: cortinico

Differential Revision: D58948614

fbshipit-source-id: 5420bdf0fda325779a4e287e7b00c623de822ccb