chore: Add theme=null export for vite build error (#37462)

* fix: Vite build error

* test: Update snapshot

* chore: Update snapshot

components/__tests__/__snapshots__/index.test.ts.snap

@@ -67,6 +67,7 @@ Array [
   "Upload",
   "message",
   "notification",
+  "theme",
   "version",
 ]
 `;

components/index.tsx

@@ -16,6 +16,9 @@ if (
 }
 /* @remove-on-es-build-end */
 
+// Fix vite build error
+export const theme = null;
+
 export { default as Affix } from './affix';
 export type { AffixProps } from './affix';
 export { default as Alert } from './alert';

tests/__snapshots__/index.test.js.snap

@@ -67,6 +67,7 @@ Array [
   "Upload",
   "message",
   "notification",
+  "theme",
   "version",
 ]
 `;