[v4] Broader changes for the story around attributes and their inheritance

[Youssef1313]

This issue serves as a proposal for changes related to attributes and how we do the reflection.

1. ALL calls to GetCustomAttributes should use inherit: true.

2. Attributes that are not inheritable (e.g, TestClassAttribute), will have Inherited = false in their attribute usage.
   This means two things:

   • Even if we use inherit: true, they are not inherited because of the attribute usage.
   • Users are allowed to introduce a new attribute, class MyTestClassAttribute : TestClassAttribute that has AttributeUsage with Inherited = true, in that case, we allow inheritance, as it's explicitly stated by the user.

More changes may be needed to have better and consistent experience, but this may be a good first step aimed for v4

cc @Evangelink