Filters that don't have any parameters shouldn't allocate an empty array

[davidfowl]

We should be using Array.Empty<object>() in this situation.

var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();

app.MapGet("/", () => {    });
.AddFilter((context, next) =>
{
    return next(context);
});

app.Run();

Type	Allocations	Bytes	Average Size (Bytes)
+ System.Object[]	21,987	667,536	30.36
| - System.Object[0]	21,003	504,072	24

Function Name	Allocations	Bytes	Module Name
+ dynamicClass.lambda_method2(00007FFA03556EC0, object, 00007FFA03071310)	21,001	504,024	anonymously hosted dynamicmethods assembly
| + Microsoft.AspNetCore.Routing.EndpointMiddleware.Invoke(Microsoft.AspNetCore.Http.HttpContext)	21,001	504,024	microsoft.aspnetcore.routing.il
|| + Microsoft.AspNetCore.Routing.EndpointRoutingMiddleware.Invoke(Microsoft.AspNetCore.Http.HttpContext)	21,001	504,024	microsoft.aspnetcore.routing.il
||| + Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke()	21,001	504,024	microsoft.aspnetcore.diagnostics.il
|||| + System.Runtime.CompilerServices.AsyncMethodBuilderCore.Start<T>(T)	21,001	504,024	System.Private.CoreLib.il
||||| + Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(Microsoft.AspNetCore.Http.HttpContext)	21,001	504,024	microsoft.aspnetcore.diagnostics.il

cc @captainsafia