Alerting: Do not persist noop transition from Normal state. (#61201)

* add feature flag `alertingNoNormalState`
* update instance database to support exclusion of state in list operation
* do not save normal state and delete transitions to normal
* update get methods to filter out normal state

pkg/services/ngalert/models/instance.go

@@ -50,10 +50,8 @@ func (i InstanceStateType) IsValid() bool {
 
 // ListAlertInstancesQuery is the query list alert Instances.
 type ListAlertInstancesQuery struct {
-	RuleOrgID   int64 `json:"-"`
-	RuleUID     string
-	State       InstanceStateType
-	StateReason string
+	RuleUID   string
+	RuleOrgID int64 `json:"-"`
 
 	Result []*AlertInstance
 }