Remove COM attributes from interfaces modified by trimming

[sbomer]

Currently, ILLink keeps COM-related attributes on any preserved COM interfaces, even when removing members from the interface. This could break scenarios where built-in COM is enabled. (Note that built-in COM is not supported when trimming).

@jkoritzinsky had a suggestion to improve this in #101087 (review):

I have another idea to avoid silent bad RCWs/CCWs: Given that this would break when built-in COM is enabled, could we remove the attributes/metadata that make an interface a COM interface if any of its members are trimmed? Then we wouldn't have the bad scenario where someone could say "don't keep COM interfaces, but keep built-in COM enabled", as if a COM interface is trimmed, it's no longer a COM interface.

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