Deprecate owned types with ordinal keys (owned JSON collections)

[roji]

With complex types fully supported in EF 10, the current owned JSON collection mapping method with ordinal keys is now considered deprecated.

[roji]

@AndriySvyryd is this a duplicate of #37290?

[AndriySvyryd]

@roji No, we should do this once we remove the deprecation for relational owned JSON support.

[roji]

OK, I don't understand but I guess it doesn't matter.