Fix warning about asyncio marker in tests

[danfimov]

Description

Made a fix to avoid asyncio marker warnings that were applied to non-asynchronous tests.

Now you do not need to put this marker in every file with asynchronous tests, as it is applied automatically.

Fix #1005

Type of change

This is just a bug fix in tests, not breaking change)

How has this been tested?

To test the fix, you can run tests and make sure there are no warnings about pytest.mark.asyncio.

Test Configuration

• All tests run with the make test command

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• New and existing unit tests pass locally with my changes
• My changes generate no new warnings or errors
• My changes are compatible with minimum requirements of the project