Tweak newly added test

[caseydavenport]

Description

I realized after merging https://github.com/projectcalico/calico/pull/6282 that the test added wasn't guaranteed to catch the situation originally intended to be fixed by that PR.

This PR makes some minor tweaks to that test to more accurately simulate the original problem situation fixed by that PR.

Related issues/PRs

Todos

• [ ] Tests
• [ ] Documentation
• [ ] Release note

Release Note

TBD

Reminder for the reviewer

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