Using JsonTypeInfo to read request body in RDF

[brunolins16]

Contributes #45527

Updating RDF to use AOT/linker-safe methods to read the request body as JSON.

Obs.: I decided to not add additional unit/functional test because the current tests cover most part of the behavior already.

Eg.:

aspnetcore/src/Http/Http.Extensions/test/RequestDelegateFactoryTests.cs

Line 1850 in 041a673

public async Task RequestDelegatePopulatesFromBodyParameter(Delegate action)

aspnetcore/src/Http/Routing/test/FunctionalTests/RouteHandlerTest.cs

Line 22 in 041a673

public async Task MapPost_FromBodyWorksWithJsonPayload()

Waiting for #45593 and #45405

[davidfowl]

This is a performance optimization, not an AOT work item. RDF has been marked unsafe for linking and AOT.