chore(python): fix erroneous versions detected in detect_versions()

[parthea]

PR #1246 added ability to detect versions recursively when detect_versions() is called, however we're seeing erroneous versions detected in python-webrisk here.

I've updated the code to stop searching subdirectories if versions are found in the parent directory. I've also added a test to confirm the behaviour.

With the code in #1246, the following versions are detected.

webrisk_v1
webrisk_v1beta1
web_risk_service_v1_beta1 <- this is erroneously detected, and it is actually a service under webrisk_v1beta1

With the code in this PR, the following versions are detected

webrisk_v1
webrisk_v1beta1

[parthea]

I tested the post processor in this commit in a PR on python-webrisk and it produced the correct result.

[parthea]

I also tested the post processor in this commit in a PR on python-phishingprotection and it produced the correct result.