Set IExceptionHandlerFeature on DeveloperExceptionPageMiddleware

[Kahbazi]

Fixes #49195

[ghost]

Thanks for your PR, @Kahbazi. Someone from the team will get assigned to your PR shortly and we'll get it reviewed.

[JamesNK]

This test isn't forcing the asserts to run. Move asserts into the main path of the test:

Suggested change

	// Arrange
	using var host = new HostBuilder()
	.ConfigureWebHost(webHostBuilder =>
	{
	webHostBuilder
	.UseTestServer()
	.Configure(app =>
	{
	app.Use(async (context, next) =>
	{
	await next();
	var exceptionHandlerFeature = context.Features.GetRequiredFeature<IExceptionHandlerPathFeature>();
	Assert.NotNull(exceptionHandlerFeature);
	Assert.Equal("Test exception", exceptionHandlerFeature.Error.Message);
	Assert.Equal(context.Request.Path, exceptionHandlerFeature.Path);
	});
	app.UseExceptionHandler(exceptionApp =>
	{
	exceptionApp.Run(context => Task.CompletedTask);
	});
	app.Run(context =>
	{
	throw new Exception("Test exception");
	});
	});
	}).Build();
	await host.StartAsync();
	var server = host.GetTestServer();
	var request = new HttpRequestMessage(HttpMethod.Get, "/path");
	var response = await server.CreateClient().SendAsync(request);
	// Arrange
	var tcs = new TaskCompletionSource<IExceptionHandlerPathFeature>(TaskCreationOptions.RunContinuationsAsynchronously);
	using var host = new HostBuilder()
	.ConfigureWebHost(webHostBuilder =>
	{
	webHostBuilder
	.UseTestServer()
	.Configure(app =>
	{
	app.Use(async (context, next) =>
	{
	await next();
	var exceptionHandlerFeature = context.Features.GetRequiredFeature<IExceptionHandlerPathFeature>();
	tcs.SetResult(exceptionHandlerFeature);
	});
	app.UseExceptionHandler(exceptionApp =>
	{
	exceptionApp.Run(context => Task.CompletedTask);
	});
	app.Run(context =>
	{
	throw new Exception("Test exception");
	});
	});
	}).Build();
	await host.StartAsync();
	var server = host.GetTestServer();
	var request = new HttpRequestMessage(HttpMethod.Get, "/path");
	var response = await server.CreateClient().SendAsync(request);
	var feature = await tcs.Task;
	Assert.NotNull(feature);
	Assert.Equal("Test exception", feature.Error.Message);
	Assert.Equal(context.Request.Path, feature.Path);

(note: changed in a text field, not might not compile, and/or have bugs)

[dotnet-policy-service]

Looks like this PR hasn't been active for some time and the codebase could have been changed in the meantime.
To make sure no conflicting changes have occurred, please rerun validation before merging. You can do this by leaving an /azp run comment here (requires commit rights), or by simply closing and reopening.

[adityamandaleeka]

@Kahbazi Are you still interested in working on this?

[Kahbazi]

@adityamandaleeka Sorry I missed this PR, I will work on it this weekend.