amis-saas-7237 [Bug] dropdown-button组件在使用时传入 popOverContainer: null情况下，buttons属性内容会渲染在当前层级下

Change-Id: I1909b4e11b2b8efff0ee37221c42753d9ee15419

packages/amis-editor-core/scss/_rightPanel.scss

@@ -280,7 +280,7 @@ $category-2-height: px2rem(32px);
     // tab导航
     ul[role='tablist'],
     &-links {
-      margin: 0 0 -1px 0;
+      margin: 0;
       flex: 0;
       border-bottom: 1px solid #d4d6d9;
       display: flex;
@@ -356,6 +356,7 @@ $category-2-height: px2rem(32px);
       padding: 0;
       overflow-y: overlay !important;
       @include minScrollBar();
+      margin-top: -1px;
     }
 
     div.ae-switch-more-flex {

packages/amis-editor-core/scss/control/_event-action.scss

@@ -14,6 +14,7 @@
     padding: #{px2rem(12px)};
     background: #fff;
     z-index: 1;
+    margin-top: 1px;
     .add-event-dropdown {
       button {
         top: 44px;