docs: remove duplicate demo classNames (ant-design#56991)

* docs:  remove unused classNames demo for Modal component

* chore: update

* chore: rm

Author: meet-student

components/modal/__tests__/__snapshots__/demo-extend.test.ts.snap

@@ -39,39 +39,6 @@ exports[`renders components/modal/demo/button-props.tsx extend context correctly
 
 exports[`renders components/modal/demo/button-props.tsx extend context correctly 2`] = `[]`;
 
-exports[`renders components/modal/demo/classNames.tsx extend context correctly 1`] = `
-<div
-  class="ant-space ant-space-horizontal ant-space-align-center ant-space-gap-row-small ant-space-gap-col-small css-var-test-id"
->
-  <div
-    class="ant-space-item"
-  >
-    <button
-      class="ant-btn css-var-test-id ant-btn-primary ant-btn-color-primary ant-btn-variant-solid"
-      type="button"
-    >
-      <span>
-        Open Modal
-      </span>
-    </button>
-  </div>
-  <div
-    class="ant-space-item"
-  >
-    <button
-      class="ant-btn css-var-test-id ant-btn-primary ant-btn-color-primary ant-btn-variant-solid"
-      type="button"
-    >
-      <span>
-        ConfigProvider
-      </span>
-    </button>
-  </div>
-</div>
-`;
-
-exports[`renders components/modal/demo/classNames.tsx extend context correctly 2`] = `[]`;
-
 exports[`renders components/modal/demo/component-token.tsx extend context correctly 1`] = `
 <div
   style="display: flex; flex-direction: column; row-gap: 16px;"

components/modal/__tests__/__snapshots__/demo.test.tsx.snap

@@ -33,37 +33,6 @@ exports[`renders components/modal/demo/button-props.tsx correctly 1`] = `
 </button>
 `;
 
-exports[`renders components/modal/demo/classNames.tsx correctly 1`] = `
-<div
-  class="ant-space ant-space-horizontal ant-space-align-center ant-space-gap-row-small ant-space-gap-col-small css-var-test-id"
->
-  <div
-    class="ant-space-item"
-  >
-    <button
-      class="ant-btn css-var-test-id ant-btn-primary ant-btn-color-primary ant-btn-variant-solid"
-      type="button"
-    >
-      <span>
-        Open Modal
-      </span>
-    </button>
-  </div>
-  <div
-    class="ant-space-item"
-  >
-    <button
-      class="ant-btn css-var-test-id ant-btn-primary ant-btn-color-primary ant-btn-variant-solid"
-      type="button"
-    >
-      <span>
-        ConfigProvider
-      </span>
-    </button>
-  </div>
-</div>
-`;
-
 exports[`renders components/modal/demo/component-token.tsx correctly 1`] = `
 <div
   style="display:flex;flex-direction:column;row-gap:16px"

components/modal/demo/classNames.md

@@ -34,7 +34,6 @@ Additionally, if you need to show a simple confirmation dialog, you can use [`Ap
 <code src="./demo/width.tsx">To customize the width of modal</code>
 <code src="./demo/static-info.tsx">Static Method</code>
 <code src="./demo/confirm.tsx">Static confirmation</code>
-<code src="./demo/classNames.tsx">Customize className for build-in module</code>
 <code src="./demo/confirm-router.tsx">destroy confirmation modal dialog</code>
 <code src="./demo/style-class.tsx" version="6.0.0">Custom semantic dom styling</code>
 <code src="./demo/nested.tsx" debug>Nested Modal</code>

components/modal/demo/classNames.tsx

@@ -35,7 +35,6 @@ demo:
 <code src="./demo/width.tsx">自定义模态的宽度</code>
 <code src="./demo/static-info.tsx">静态方法</code>
 <code src="./demo/confirm.tsx">静态确认对话框</code>
-<code src="./demo/classNames.tsx">自定义内部模块 className</code>
 <code src="./demo/confirm-router.tsx">销毁确认对话框</code>
 <code src="./demo/style-class.tsx" version="6.0.0">自定义语义结构的样式和类</code>
 <code src="./demo/nested.tsx" debug>嵌套弹框</code>