Use tty for running docker commands by default

[mathbunnyru]

Describe your changes

Issue ticket if applicable

Checklist (especially for first-time contributors)

• I have performed a self-review of my code
• If it is a core feature, I have added thorough tests
• I will try not to use force-push to make the review process easier for reviewers
• I have updated the documentation for significant changes

[mathbunnyru]

I first made our tests work fine without tty (and fixed a bug in our start script) and unified tests, but now I want to have tty by default:

• sometimes we have different results with tty and without it, so it's nice to have the tests which work fine in both cases and to control from one place if tty is enabled (unfortunately, before, TTY flag was quite random)
• by default I want to have tty enabled: the output is coloured, which makes debugging much easier when something fails

[mathbunnyru]

This is the only test which fails with tty enabled (I tested base-notebook locally).
It also fails when running manually:
docker run -it --user 1010 quay.io/jupyter/base-notebook:latest id
If I remove -t, then it gives expected output.

The source of /usr/local/bin/before-notebook.d/10activate-conda-env.sh unfortunately doesn't work

[mathbunnyru]

Got it, I removed the script in the image, and then ran it's content manually (eval "$(conda shell.bash hook)") and in the end it gives:

Would you like conda to send this report to the core maintainers? [y/N]:

So in a non-interactive mode it just finishes, but in interactive it fails after timeout.

[mathbunnyru]

And it fails after 40 seconds which is more than our timeout, that's why test reports as failed

https://github.com/conda/conda/blob/4691c2826d5282637674de754b504c2f045e23d5/conda/exception_handler.py#L285

[mathbunnyru]

Setting report_errors in config won't work here, because in this test the /home/jovyan is not accessible.

So the best we can do is to put a link why we need to disable tty there, at least now I know the reason.