Auth: Fix Last Seen being updated on every request (#72036)

* make sure LastSeen hook has information to decide if update is necessary

* make user service check if it should update the user's last seen

* do not run last seen hook if is a login request

* make service return error when last seen is up to date

* fix err

* Update pkg/services/contexthandler/contexthandler.go

Co-authored-by: Gabriel MABILLE <gamab@users.noreply.github.com>

* fix golint

---------

Co-authored-by: Gabriel MABILLE <gamab@users.noreply.github.com>

pkg/services/user/model.go

@@ -27,6 +27,7 @@ var (
 	ErrLastGrafanaAdmin  = errors.New("cannot remove last grafana admin")
 	ErrProtectedUser     = errors.New("cannot adopt protected user")
 	ErrNoUniqueID        = errors.New("identifying id not found")
+	ErrLastSeenUpToDate  = errors.New("last seen is already up to date")
 )
 
 type User struct {
@@ -95,6 +96,7 @@ type ChangeUserPasswordCommand struct {
 
 type UpdateUserLastSeenAtCommand struct {
 	UserID int64
+	OrgID  int64
 }
 
 type SetUsingOrgCommand struct {