Flaky test: TestLoader_ShouldCacheIndexNotFoundOnBackgroundUpdates

[dsabsay]

--- FAIL: TestLoader_ShouldCacheIndexNotFoundOnBackgroundUpdates (1.00s)
    loader_test.go:480: 
        	Error Trace:	/__w/cortex/cortex/pkg/storage/tsdb/bucketindex/loader_test.go:480
        	Error:      	Received unexpected error:
        	            	 # HELP cortex_bucket_index_loaded Number of bucket indexes currently loaded in-memory.
        	            	 # TYPE cortex_bucket_index_loaded gauge
        	            	-cortex_bucket_index_loaded 1
        	            	+cortex_bucket_index_loaded 0
        	            	 
        	Test:       	TestLoader_ShouldCacheIndexNotFoundOnBackgroundUpdates
FAIL
FAIL	github.com/cortexproject/cortex/pkg/storage/tsdb/bucketindex	7.797s

Seen here: https://github.com/cortexproject/cortex/actions/runs/12943227785/job/36102225793

[dsabsay]

I am working on this.

[stale]

This issue has been automatically marked as stale because it has not had any activity in the past 60 days. It will be closed in 15 days if no further activity occurs. Thank you for your contributions.