Fix tracked time issues (#11349) (#11354)

Backport #11349 

* Fix tracked time issues (#11349)

* Fix nil exeption: #11313

* fix 500

* activate test 😆

* move logic

* Add missing import

Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: Guillermo Prandi <guillep2k@users.noreply.github.com>

routers/api/v1/repo/issue_tracked_time.go

@@ -5,6 +5,7 @@
 package repo
 
 import (
+	"fmt"
 	"net/http"
 	"time"
 
@@ -296,6 +297,10 @@ func DeleteTime(ctx *context.APIContext) {
 		ctx.Error(http.StatusInternalServerError, "GetTrackedTimeByID", err)
 		return
 	}
+	if time.Deleted {
+		ctx.NotFound(fmt.Errorf("tracked time [%d] already deleted", time.ID))
+		return
+	}
 
 	if !ctx.User.IsAdmin && time.UserID != ctx.User.ID {
 		//Only Admin and User itself can delete their time