Handle worker version creation with an existing revision_url

This check was missing after merging !2402 (merged), causing a HTTP 500.

requested review from @erouchet

assigned to @vrigal

added 3 commits

• a2d1e69b - 1 commit from branch master
• 5557641b - Update tests
• be0a9a93 - Add check

Compare with previous version

enabled an automatic merge when the pipeline for be0a9a93 succeeds

merged