fix: make Enums usable inside CollectionColumnType

[RafaelKr]

closes #203

[Kreyu]

Hey @RafaelKr, thanks for the report and for the pull request. However, I would say CollectionColumnType should not strictly check for enums. I've been checking different scenarios and it looks like the issue occurs for non-scalar values - enums, date time, objects, and much more.

I tried multiple solutions and found a (it seems like) universal one - if there's no property_path or getter in entry_options, I'm defaulting to a getter that simply returns the value, and it works fine. I fixed that in 0.29.2.

Thanks again!