style(测试计划): 功能用例-执行脑图-调整底部批量操作的位置

--bug=1048405 --user=吕梦园
https://www.tapd.cn/55049933/bugtrace/bugs/view/1155049933001048405

frontend/src/components/pure/ms-minder-editor/menu/batchMenu.vue

@@ -1,5 +1,11 @@
 <template>
-  <div v-if="batchMenuVisible" class="ms-minder-node-float-menu ms-minder-batch-menu">
+  <a-affix
+    v-if="batchMenuVisible"
+    :offset-bottom="32"
+    target-container=".page-content"
+    class="absolute bottom-0 left-[50%]"
+  >
+    <div class="ms-minder-batch-menu">
       <a-dropdown
         v-if="props.priorityCount && props.canShowPriorityMenu"
         v-model:popup-visible="priorityMenuVisible"
@@ -92,6 +98,7 @@
         </template>
       </a-dropdown>
     </div>
+  </a-affix>
 </template>
 
 <script setup lang="ts">
@@ -187,12 +194,13 @@
 
 <style lang="less" scoped>
   .ms-minder-batch-menu {
-    @apply absolute flex w-auto flex-1 items-center bg-white;
+    @apply absolute flex w-auto flex-1 items-center;
 
     bottom: 6px;
     left: 50%;
     padding: 4px 8px;
     border-radius: var(--border-radius-small);
+    background-color: var(--color-text-fff);
     box-shadow: 0 4px 10px -1px rgb(100 100 102 / 15%);
     gap: 8px;
   }