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.IntegrationTests/DummyGameTicker.cs

@@ -75,7 +75,7 @@ namespace Content.IntegrationTests
 
         public T AddGameRule<T>() where T : GameRule, new()
         {
-            return new T();
+            return new();
         }
 
         public bool HasGameRule(Type type)
@@ -120,7 +120,7 @@ namespace Content.IntegrationTests
 
         public Dictionary<string, int> GetAvailablePositions()
         {
-            return new Dictionary<string, int>();
+            return new();
         }
     }
 }