优化AI聊天组件显示逻辑

src/views/components/aiChat/aiArgenChat.vue

 <template>
     <div class="AiLibrary">
-        <div class="aiLibraryContent" v-if="knowledge_search_list.length > 2">
+        <div class="aiLibraryContent" v-if="knowledge_search_list.length > 0">
             <div class="aiLibraryHeader">
                 <div class="aiLibraryHeader_content columnFlex">
                     <div class="rowFlex rowCenter spaceBetween">