Chore: remove custom Vitest JSX esbuild config (#7234)

vitest.config.mjs

@@ -3,11 +3,6 @@ import { fileURLToPath, URL } from "node:url";
 import { defineConfig } from "vitest/config";
 
 export default defineConfig({
-  // Next.js handles JSX via SWC; Vitest uses Vite/esbuild, so enable the modern JSX runtime
-  // to avoid requiring `import React from "react"` in every JSX file.
-  esbuild: {
-    jsx: "automatic",
-  },
   resolve: {
     alias: {
       components: fileURLToPath(new URL("./src/components", import.meta.url)),