tox4 values cannot contain whitespace

[kokobhara]

Describe the bug
tox4 does not support pass_env values with whitespace in tox.ini

To Reproduce
$ tox -e dev

Output
tox.tox_env.errors.Fail: pass_env values cannot contain whitespace, use comma to have multiple values in a single line, invalid values found 'HOME LANG LC_ALL'

Environment (please complete the following information):

• OS: macOS Ventura
• Python Version: 3.10
• pytest-flask version: 1.0.1