conda python breaks the python tests #18219
Description
For a user running through https://beam.apache.org/contribute/contribution-guide/#one-time-setup, the first time they run mvn verify the Python tests will fail if they have a conda python instance on their path.
To make the getting started experience easier for new devs we should call out that conda is not supported given its popularity.
cc [~altay]
Imported from Jira BEAM-2087. Original Jira may contain additional context.
Reported by: holden.