Alerting: Fix Classic Conditions $values variable (#64243)

This commit fixes a bug in the $values variable in notification
templates when using Classic Conditions. Since Classic Conditions
are not multi-dimensional, the values of each series that exceeded
the condition should be available as a RefID and offset. For example,
B0, B1, etc. However, this bug meant that instead just a single
condition would be printed as B, not B0.

pkg/services/ngalert/state/cache.go

@@ -52,11 +52,11 @@ func (rs *ruleStates) getOrCreate(ctx context.Context, log log.Logger, alertRule
 	ruleLabels, annotations := rs.expandRuleLabelsAndAnnotations(ctx, log, alertRule, result, extraLabels, externalURL)
 
 	values := make(map[string]float64)
-	for _, v := range result.Values {
+	for refID, v := range result.Values {
 		if v.Value != nil {
-			values[v.Var] = *v.Value
+			values[refID] = *v.Value
 		} else {
-			values[v.Var] = math.NaN()
+			values[refID] = math.NaN()
 		}
 	}