text: Title: [4.12.0][regression] The presence of `TOX_PARALLEL_NO_SPINNER=1` in CI suppresses output of single env run tox commands
  Body: ## Issue
  
  I have a number for globally set environment variables, one of each is `TOX_PARALLEL_NO_SPINNER`: https://github.com/ansible/pylibssh/blob/ef77a85/.github/workflows/ci-cd.yml#L75.
  
  In one of the steps, I run `tox -e a-single-env -qq | tee a-file.txt`. In tox 4.11.4, it produces output from the command specified in `tox.ini`. Starting with tox 4.12.0, the output is empty.
  
  I'm pretty convinced this is a side effect of #3159.
  
  Previously, setting this var allowed having it in one place, while allowing for parallel and non-parallel runs different job steps, not having to track whether to disable or enable the spinner in each. So I consider this to be a regression.
  
  ## Environment
  
  - OS: ubuntu-latest @ GHA
  
  `tox == 4.12.0`
  
  ## Output of running tox
  
  No output.
  
  ## Minimal example
  
  ```console
  $ TOX_PARALLEL_NO_SPINNER=1 tox -e a-single-env --skip-pkg-install -qq
  ```
  