fix #7897 保证用户粘贴时粘贴板为图片才会自动展开进行图片上床逻辑

src/components/Editor/index.js

@@ -180,6 +180,7 @@ class Editor extends React.Component {
           break;
         }
       }
+      if (file === null) return;
     }
     this.setState({
       uploadVisible: true