Use 'new' expression in places where the type is evident for content (#2590)

* Content.Client

* Content.Benchmarks

* Content.IntegrationTests

* Content.Server

* Content.Server.Database

* Content.Shared

* Content.Tests

* Merge fixes

Co-authored-by: metalgearsloth <31366439+metalgearsloth@users.noreply.github.com>

Content.Client/ClientNotifyManager.cs

@@ -29,7 +29,7 @@ namespace Content.Client
         [Dependency] private readonly IClientNetManager _netManager = default!;
         [Dependency] private readonly IEntityManager _entityManager = default!;
 
-        private readonly List<PopupLabel> _aliveLabels = new List<PopupLabel>();
+        private readonly List<PopupLabel> _aliveLabels = new();
         private bool _initialized;
 
         public void Initialize()