Downgrade ESLint to v8 (#10888)

## Summary

Some of our plugins aren't compatible with v9.

Originally shipped in #10827.

## Test Plan

- `npm install`
- `npm ci`

Author: charliermarsh

playground/package-lock.json

@@ -30,9 +30,9 @@
     "@typescript-eslint/parser": "^7.0.0",
     "@vitejs/plugin-react-swc": "^3.0.0",
     "autoprefixer": "^10.4.13",
-    "eslint": "^9.0.0",
+    "eslint": "^8.30.0",
     "eslint-config-prettier": "^9.0.0",
-    "eslint-plugin-import": "^2.26.0",
+    "eslint-plugin-import": "^2.29.1",
     "eslint-plugin-prettier": "^5.0.0",
     "eslint-plugin-react": "^7.31.11",
     "eslint-plugin-react-hooks": "^4.6.0",