fix: app-tools import createServer.js (#6169)

Co-authored-by: Belinda Cao <caohuilin@bytedance.com>

Author: keepview

.changeset/gentle-sloths-pretend.md

@@ -0,0 +1,5 @@
+---
+'@modern-js/app-tools': patch
+---
+
+fix: app-tools import createServer.js to fix errors during HMR

packages/solutions/app-tools/src/index.ts

@@ -157,7 +157,7 @@ export const appTools = (
         const { filename, eventType, isPrivate } = e;
 
         if (!isPrivate && (eventType === 'change' || eventType === 'unlink')) {
-          const { closeServer } = await import('./utils/createServer');
+          const { closeServer } = await import('./utils/createServer.js');
           await closeServer();
           await restart(api.useHookRunners(), filename);
         }