Implement unidirectional GeneratedComInterface options

[jkoritzinsky]

Fixes #86360

We don't have a good hook to stop casting to a generated COM interface, so casts to "managed object wrapper"-only interfaces would still succeed if the QI is successful, but calling any methods would fail. Given that we expect most interfaces to use the default bidirectional behavior and only use the unidirectional cases for scenarios when they know it will only be used in one direction, I think the behavior is fine.

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Issue Details

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Fixes #86360

We don't have a good hook to stop casting to a generated COM interface, so casts to "managed object wrapper"-only interfaces would still succeed if the QI is successful, but calling any methods would fail. Given that we expect most interfaces to use the default bidirectional behavior and only use the unidirectional cases for scenarios when they know it will only be used in one direction, I think the behavior is fine.

Author:	jkoritzinsky
Assignees:	-
Labels:	area-System.Runtime.InteropServices, source-generator
Milestone:	8.0.0

[jtschuster]

LGTM