RBAC: Fix authorize in org (#81552)

* RBAC: Fix authorize in org

* Implement option 2

* Fix typo

* Fix alerting test

* Add test to cover the not member case

pkg/services/authn/identity.go

@@ -31,6 +31,7 @@ const (
 
 const (
 	AnonymousNamespaceID = NamespaceAnonymous + ":0"
+	GlobalOrgID          = int64(0)
 )
 
 var _ identity.Requester = (*Identity)(nil)
@@ -164,6 +165,19 @@ func (i *Identity) GetPermissions() map[string][]string {
 	return i.Permissions[i.GetOrgID()]
 }
 
+// GetGlobalPermissions returns the permissions of the active entity that are available across all organizations
+func (i *Identity) GetGlobalPermissions() map[string][]string {
+	if i.Permissions == nil {
+		return make(map[string][]string)
+	}
+
+	if i.Permissions[GlobalOrgID] == nil {
+		return make(map[string][]string)
+	}
+
+	return i.Permissions[GlobalOrgID]
+}
+
 func (i *Identity) GetTeams() []int64 {
 	return i.Teams
 }