Bump json_annotation from 4.4.0 to 4.5.0 in /experimental/web_dashboard (#1176)

Bumps [json_annotation](https://github.com/google/json_serializable.dart) from 4.4.0 to 4.5.0.
- [Release notes](https://github.com/google/json_serializable.dart/releases)
- [Commits](https://github.com/google/json_serializable.dart/compare/json_annotation-v4.4.0...json_annotation-v4.5.0)

---
updated-dependencies:
- dependency-name: json_annotation
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

experimental/web_dashboard/pubspec.yaml

@@ -12,7 +12,7 @@ dependencies:
   firebase_auth: ^3.3.16
   firebase_core: ^1.15.0
   google_sign_in: ^5.0.0
-  json_annotation: ^4.1.0
+  json_annotation: ^4.5.0
   provider: ^6.0.0
   uuid: ^3.0.0
   charts_flutter: ^0.12.0