Improve error handling for connection timeout

[ShivaniKumar1]

During this specific block in the buildpack:
https://github.com/heroku/heroku-buildpack-python/blob/main/bin/steps/python#L18-L26
The error being returned is misleading. The error that should be returned should be something like
output::error <<-EOF Error: Python Connection timeout error EOF meta_set "failure_reason" "connection-timeout"
The error "python version not found" has nothing to do with the connection being timeout.