Add feature switch to disable COM type descriptors

[sbomer]

Together with dotnet/winforms#11165, this removes some COM-related trim warnings in a winforms test app by disabling support for browsing COM objects via the TypeDescriptor APIs.

[ghost]

Note regarding the new-api-needs-documentation label:

This serves as a reminder for when your PR is modifying a ref *.cs file and adding/modifying public APIs, please make sure the API implementation in the src *.cs file is documented with triple slash comments, so the PR reviewers can sign off that change.

[dotnet-policy-service]

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