backport(net8.0): http.sys on-demand TLS client hello retrieval

[DeagleGross]

Http.Sys on-demand tls client hello bytes fetch to net8.

Description

Backporting #62209 to release/net8.0.
Changes API to have a byte[] input parameter, because Span<byte> is not really compatible with reflection. So it becomes bool TryGetTlsClientHello(byte[] tlsClientHelloBytesDestination, out int bytesReturned);

Usage example is in the sample app and commented to be a recommended approach (compared to callback API; as on-demand API will be an only API existing in net10):

var httpSysAssembly = typeof(Microsoft.AspNetCore.Server.HttpSys.HttpSysOptions).Assembly;
var httpSysPropertyFeatureType = httpSysAssembly.GetType("Microsoft.AspNetCore.Server.HttpSys.IHttpSysRequestPropertyFeature");
var httpSysPropertyFeature = context.Features[httpSysPropertyFeatureType]!;

var method = httpSysPropertyFeature.GetType().GetMethod(
   "TryGetTlsClientHello",
   BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic
);

// invoke first time to get required size
byte[] bytes = Array.Empty<byte>();
var parameters = new object[] { bytes, 0 };
var res = (bool)method.Invoke(httpSysPropertyFeature, parameters);

// fetching out parameter only works by looking into parameters array of objects
var bytesReturned = (int)parameters[1];
bytes = ArrayPool<byte>.Shared.Rent(bytesReturned);
parameters = [bytes, 0]; // correct input now
res = (bool)method.Invoke(httpSysPropertyFeature, parameters);

// this is the span representing the TLS Client Hello bytes only
var tlsClientHelloBytes = ((byte[])parameters[0]).AsSpan(0, bytesReturned);
await context.Response.WriteAsync($"TlsBytes: {string.Join(" ", tlsClientHelloBytes.Slice(0, 10).ToArray())}; full length = {bytesReturned}");

ArrayPool<byte>.Shared.Return(bytes);

Fixes #61625

Customer Impact

Allows customers to inspect the TLS Client Hello message on-demand instead of following the callback API.
Existing #61494 callback API showed issues with race-conditions (processing callback at the same time as serving other requests).

Regression?

• Yes
• No

Risk

• High
• Medium
• Low

Fully opt-in feature so won't affect existing code. Also, if it is turned on, there are a few app context knobs to tweak behavior in case something goes wrong.

Verification

• Manual (required)
• Automated

Packaging changes reviewed?

• Yes
• No
• N/A

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