chore(deps): bump @angular/ssr from 21.0.0 to 21.2.1 in /demo

Bumps [@angular/ssr](https://github.com/angular/angular-cli) from 21.0.0 to 21.2.1.
- [Release notes](https://github.com/angular/angular-cli/releases)
- [Changelog](https://github.com/angular/angular-cli/blob/main/CHANGELOG.md)
- [Commits](angular/angular-cli@21.0.0...v21.2.1)

---
updated-dependencies:
- dependency-name: "@angular/ssr"
  dependency-version: 21.2.1
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

demo/package-lock.json

@@ -20,7 +20,7 @@
     "@angular/platform-browser-dynamic": "^21.0.0-rc.1",
     "@angular/platform-server": "^21.0.0-rc.1",
     "@angular/router": "^21.0.0-rc.1",
-    "@angular/ssr": "^21.0.0-rc.1",
+    "@angular/ssr": "^21.2.1",
     "@netlify/angular-runtime": "file:..",
     "@netlify/edge-functions": "^3.0.2",
     "express": "^4.21.0",