chore: remove pnpm devDependency

ref: vitejs/vite#11758

Author: sxzz

package.json

@@ -59,7 +59,6 @@
     "npm-run-all": "^4.1.5",
     "picocolors": "^1.0.0",
     "playwright-chromium": "^1.37.1",
-    "pnpm": "^7.33.6",
     "prettier": "3.0.2",
     "resolve": "^1.22.4",
     "rollup": "^3.28.0",