Change assertion from flash to breadcrumb

What does this MR do and why?

Related to #384966 (closed)

The spec in the above related issue is flaky and has been quarantined. It is flaky because we are making an assertion on a flash which can have issues with race conditions. In feature spec docs we advise against making assertions on flashes because of this issue.

For more information about race conditions see #385232

MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.