Bump http from 1.5.0 to 1.6.0 in /dashboard (#4883)

Bumps [http](https://github.com/dart-lang/http/tree/master/pkgs) from 1.5.0 to 1.6.0.
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Author: dependabot[bot]

dashboard/pubspec.yaml

@@ -23,7 +23,7 @@ dependencies:
   google_sign_in: ^7.0.0
   google_sign_in_platform_interface: ^3.0.0
   google_sign_in_web: ^1.0.0
-  http: 1.5.0 # Rolled by dependabot
+  http: 1.6.0 # Rolled by dependabot
   json_annotation: ^4.9.0
   meta: any # Match Flutter SDK
   provider: 6.1.5 # Rolled by dependabot