Support Clerk Core 2 (@clerk/clerk-react@5 and @clerk/nextjs@5) (#32054)

No library changes were necessary so Clerk Core 1 auth works the same. See docs on upgrade instructions from Clerk at https://clerk.com/docs/upgrade-guides/core-2/overview. Convex already allowed `@clerk/clerk-react@^5.0.0` as an optional peer dependency but now demos have also been upgraded.

Changes include deprecation of authMiddleware, which does not protect any routes by default. If upgrading an existing project be sure to read follow the Clerk-provided guide.

Many other APIs are deprecated.

GitOrigin-RevId: 2d303a54d1fcc5b3a9c5b287bad85f91169bb809

package.json

@@ -265,7 +265,7 @@
     "@auth0/auth0-react": "2.0.1",
     "@babel/parser": "^7.21.3",
     "@babel/types": "7.24.0",
-    "@clerk/clerk-react": "4.18.0",
+    "@clerk/clerk-react": "^5.18.2",
     "@commander-js/extra-typings": "^11.1.0",
     "@eslint/compat": "~1.1.1",
     "@eslint/eslintrc": "~3.1.0",