E2E test: fix test case number for vulnerability ai feature

What does this MR do and why?

This test failed in canary-staging, but a failure issue was not created, so after investigating I found the following in the job log: https://ops.gitlab.net/gitlab-org/quality/canary/-/jobs/11967343#L1559

I'm not sure if this is the cause of no failure issue being created, but it should be fixed.

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