Fixed install.php not redirecting when it should (#9224)

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app/Http/Kernel.php

@@ -29,6 +29,7 @@ class Kernel extends HttpKernel
      */
     protected $middlewareGroups = [
         'web' => [
+            \App\Http\Middleware\CheckInstalled::class,
             \App\Http\Middleware\EncryptCookies::class,
             \Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse::class,
             \Illuminate\Session\Middleware\StartSession::class,