remove engine field (#4841)

# What this PR does

remove engine field so that `yarn install` works on different versions
of Node.js


## Checklist

- [ ] Unit, integration, and e2e (if applicable) tests updated
- [x] Documentation added (or `pr:no public docs` PR label added if not
required)
- [x] Added the relevant release notes label (see labels prefixed w/
`release:`). These labels dictate how your PR will
    show up in the autogenerated release notes.

grafana-plugin/package.json

@@ -126,9 +126,6 @@
     "webpack-cli": "^5.1.4",
     "webpack-livereload-plugin": "^3.0.2"
   },
-  "engines": {
-    "node": "20.x"
-  },
   "dependencies": {
     "@dnd-kit/core": "^6.0.8",
     "@dnd-kit/modifiers": "^7.0.0",