Fixes bug 4305, which no prompts to installs a pyenv python version that doesn't exist

[philjc]

The issue

Fixes bug #4305 introduced in c23e57b which no longer identifies if the tty session is interactive. Which prevents pipenv from using pyenv to install a version of python that doesn't exist in pyenv

When this commit migrated to use vistir._isatty it bypassed os.isatty which supports fileno while vistir._isatty does not. Also since vistir._isatty swallows all exceptions we no longer need to catch UnsupportedOperation

The fix

Instead of passing in the sys.stdout.fileno() to vistir._isatty pass in the stream

The checklist

• Associated issue
• A news fragment in the news/ directory to describe this fix with the extension .bugfix, .feature, .behavior, .doc. .vendor. or .trivial (this will appear in the release changelog).

[techalchemy]

Great catch... this is definitely a huge issue, thanks for the PR!