This has been implemented in a few different ways (see MR !7238 and MR !359), neither of which have associated tests.
This way of doing things sidesteps the need to update existing `VT_BLOB` properties by just storing/retrieving them in the same format we always have. If the registry data doesn't match a set of criteria, we treat it as `VT_BLOB` always.
-- v2: mmdevapi: Add support for storing VT_CLSID properties. mmdevapi: Add support for storing VT_BOOL properties.