Returntype incorrect for UnitTestCase::getConfigFactoryStub()

Seems minor enough.

Committed/pushed to 11.x and cherry-picked to 10.1.x, thanks!

Commit don't show up. Here is the lint to the commit:
https://git.drupalcode.org/project/drupal/-/commit/dcd0ec7160cfa09cf700954b629775c5267ed0f9

Automatically closed - issue fixed for 2 weeks with no activity.

I will note that while this is better with the '|' condition used in this issue, it still is not accurate, it should have been an intersecting '&'

Incompatible types: Expected property of type '\Drupal\Core\Config\ConfigFactoryInterface&\PHPUnit\Framework\MockObject\MockObject', '\Drupal\Core\Config\ConfigFactoryInterface|\PHPUnit\Framework\MockObject\MockObject' provided.