Limit label list height on edit issue page (#10216)

web_src/less/_repository.less

@@ -158,6 +158,8 @@
         }
 
         &.labels {
+            max-height: 300px;
+
             .label-filter .menu .info {
                 display: inline-block;
                 padding: 9px 7px 7px 7px;