[Azure Monitor Distro] Duplicate attribute definition

[m-redding]

Library name

Azure.Monitor.OpenTelemetry.AspNetCore

Please describe the feature.

The file UnconditionalSuppressMessageAttribute.cs added in #38848 adds an attribute that we provide through Azure.Core in TrimmingAttribute.cs. Having both is causing conflicts and failing the core ci pipeline.

You should be able to remove this file and just add a reference to the TrimmingAttribute.cs file available through Azure.Core shared source. They were both added to solve the same problem so it should be equivalent to use either option.

This is blocking:

• [Core] Adding attributes to support Native AOT compiling #37734