Skip search command for gemnasium-python

Skip search, analyze, and convert command when testing gemnasium-python project.

This change is needed because gemnasium-python no longer uses common/v2/command, and its CLI no longer responds to search, analyze, and convert.

See gitlab-org/security-products/analyzers/gemnasium-python!84 (comment 486795991)

Follow-up: remove gitlab-org/security-products/analyzers/gemnasium-python!84 (merged)