Fixed boards card dragging styling

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/61050

app/assets/javascripts/boards/components/board_card.vue

@@ -83,7 +83,7 @@ export default {
     }"
     :index="index"
     :data-issue-id="issue.id"
-    class="board-card position-relative p-3 rounded"
+    class="board-card p-3 rounded"
     @mousedown="mouseDown"
     @mousemove="mouseMove"
     @mouseup="showIssue($event)"

app/assets/stylesheets/pages/boards.scss

@@ -210,6 +210,7 @@
   border: 1px solid $gray-200;
   box-shadow: 0 1px 2px $issue-boards-card-shadow;
   line-height: $gl-padding;
+  list-style: none;
 
   &:not(:last-child) {
     margin-bottom: $gl-padding-8;