fix: clear the load-failure bit when GetConfig reloads a bucket on demand

A successful on-demand load makes the bucket resident, so the failure
recorded by an earlier startup or refresh no longer applies. Clearing it here
keeps the set's invariant exact instead of waiting for the next refresh.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PvgysXDmhPBBimCReYtA8q
Signed-off-by: Feng Ruohang <rh@vonng.com>

cmd/bucket-metadata-sys.go

@@ -595,6 +595,7 @@ func (sys *BucketMetadataSys) GetConfig(ctx context.Context, bucket string) (met
 	}
 	sys.Lock()
 	sys.metadataMap[bucket] = meta
+	sys.clearLoadFailure(bucket)
 	sys.Unlock()
 
 	return meta, true, nil