HTML Report: Error report displays wrong failure message when Response Assertion checks Ignore Status and response code is not 200

@pmouawad ([Bug 65885](https://bz.apache.org/bugzilla//show_bug.cgi?id=65885&redirect=false)):
See attached screenshot showing Response Assertion that:

- has Ignore status checked
- has a Pattern to test: 403|404 and custom failure set to Mensch Maier!

HTML report shows as error:

- 404/Not Found (https://github.com/apache/jmeter/blob/master/src/core/src/main/java/org/apache/jmeter/report/processor/ErrorsSummaryConsumer.java#L90)

While it should display as BackendListener:

- Mensch Maier! (https://github.com/apache/jmeter/blob/master/src/components/src/main/java/org/apache/jmeter/visualizers/backend/ErrorMetric.java#L44)

Created attachment [BUG_REPORT_BACKEND_GRAFANA_ERROR.png](https://apache.github.io/jmeter-bugzilla-attachments/85/65885/38192/BUG_REPORT_BACKEND_GRAFANA_ERROR.png): Grafana OK

Severity: normal
OS: All