Create an example Otter test showing how to ignore log markers for a period of time

It is possible to verify there are no errors in the logs, except for a specific part of the test. Add an example test and documentation explaining how to do this.

Start by locating existing Otter example tests and the documentation for log-marker verification. Add an example covering the period in which expected log errors are ignored, and document how to use it. Done means the example and its explanation clearly show the intended behavior and pass the relevant test checks.

Written by the indexing model from the issue text.