Added a new integration test to verify cortex_ruler_write_requests_failed_total is incremented

Signed-off-by: Anand Rajagopal <anrajag@amazon.com>

Author: rajagopalanand

CHANGELOG.md

@@ -1,7 +1,7 @@
 # Changelog
 
 ## master / unreleased
-* [CHANGE] Ruler: Added user label to ruler query and write metrics
+* [CHANGE] Ruler: Added user label to `cortex_ruler_write_requests_total`, `cortex_ruler_write_requests_failed_total`, `cortex_ruler_queries_total`, and `cortex_ruler_queries_failed_total` metrics
 * [CHANGE] Alertmanager: Validating new fields on the PagerDuty AM config. #5290
 * [CHANGE] Ingester: Creating label `native-histogram-sample` on the `cortex_discarded_samples_total` to keep track of discarded native histogram samples. #5289
 * [FEATURE] Store Gateway: Add `max_downloaded_bytes_per_request` to limit max bytes to download per store gateway request.