Update react to v19 (major) (#18464)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

website/package.json

@@ -23,8 +23,8 @@
     "codemirror-graphql": "2.2.4",
     "graphql": "16.12.0",
     "prism-react-renderer": "2.4.1",
-    "react": "18.3.1",
-    "react-dom": "18.3.1",
+    "react": "19.2.1",
+    "react-dom": "19.2.1",
     "react-markdown": "10.1.0",
     "react-tweet": "3.2.2",
     "vue": "3.5.25"