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.Server/StationEvents/PowerGridCheck.cs

@@ -37,7 +37,7 @@ namespace Content.Server.StationEvents
 
         private CancellationTokenSource _announceCancelToken;
 
-        private readonly List<IEntity> _powered = new List<IEntity>();
+        private readonly List<IEntity> _powered = new();
 
         public override void Startup()
         {