Warn instead of reporting an error when a webhook cannot be found (#26039)

Attemp fix: #25744
Fixing the log level when we delete any repo then we get error hook not
found by id. That should be warn level to reduce the noise in the logs.

---------

Co-authored-by: delvh <dev.lh@web.de>

services/webhook/webhook.go

@@ -5,6 +5,7 @@ package webhook
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"strings"
 
@@ -111,7 +112,11 @@ func handler(items ...int64) []int64 {
 	for _, taskID := range items {
 		task, err := webhook_model.GetHookTaskByID(ctx, taskID)
 		if err != nil {
+			if errors.Is(err, util.ErrNotExist) {
+				log.Warn("GetHookTaskByID[%d] warn: %v", taskID, err)
+			} else {
 				log.Error("GetHookTaskByID[%d] failed: %v", taskID, err)
+			}
 			continue
 		}