Problem details sample returns Division_by_zero when it should return 404

[Rick-Anderson]

Problem details code returns

{"type":"https://wikipedia.org/wiki/Division_by_zero",
"title":"Wrong Input",
"status":404,
"detail":"Divison by zero is not defined."}

When there is no endpoint rather than just 404.

@sammychinedu2ky fixed that by adding HasPath, but that's an error prone solution.

@brunolins16 can you suggest a better mechanism to detect when there's no matching endpoint?

[sammychinedu2ky]

ooh ok let me do that

[brunolins16]

@Rick-Anderson sorry that I missed that in the first PR but can we maybe we could do:

1. Remove the custom middleware and Set the Feature when needed.

   AspNetCore.Docs.Samples/fundamentals/middleware/problem-details-service/Program.cs

   Line 47 in 3ebbb8b

   app.Use(async (context, next) =>

2. Have the feature always there but add a new option to the [MathErrorType], eg.: NoError and check this in the CustomizeProblemDetails. (https://github.com/dotnet/AspNetCore.Docs.Samples/blob/main/fundamentals/middleware/problem-details-service/MathErrorType.cs)

In both cases i think we could use the Get instead of GetRequiredFeature and check if not null here

AspNetCore.Docs.Samples/fundamentals/middleware/problem-details-service/Program.cs

Line 16 in 3ebbb8b

.GetRequiredFeature<MathErrorFeature>();

Similar to what I suggested here: #25 (comment)

[Rick-Anderson]

Fixed in #42