fix: custom validator check failed for prop "placement" (#1851)

[VueTypes warn]: oneOf - value should be one of "topLeft", "topCenter", "topRight", "bottomLeft", "bottomCenter", "bottomRight".
[Vue warn]: Invalid prop: custom validator check failed for prop "placement".

src/components/Table/src/components/settings/SizeSetting.vue

@@ -4,7 +4,7 @@
       <span>{{ t('component.table.settingDens') }}</span>
     </template>
 
-    <Dropdown placement="bottom" :trigger="['click']" :getPopupContainer="getPopupContainer">
+    <Dropdown placement="bottomCenter" :trigger="['click']" :getPopupContainer="getPopupContainer">
       <ColumnHeightOutlined />
       <template #overlay>
         <Menu @click="handleTitleClick" selectable v-model:selectedKeys="selectedKeysRef">