fix: recursively convert struct to dict

[fernandezcuesta]

Description of your changes

Converting metadata struct to a dict should return a nested dict, rather than a dict with e.g. annotations as a struct.

I have:

Read and followed Crossplane's [contribution process](https://git.io/fj2m9).
- [X] Added or updated unit tests for my change.

[fernandezcuesta]

unsure about whether or not we want to keep the previous behaviour as default, while allowing a "recursive" struct_to_dict via an additional argument :/

[bobh66]

unsure about whether or not we want to keep the previous behaviour as default, while allowing a "recursive" struct_to_dict via an additional argument :/

Good question - I tend to think the existing behavior is "wrong" since I would have expected nested translation, but it could be breaking if people are already used to having to convert the child objects. I'd still lean toward changing it though.

@negz any thoughts?

[negz]

Yeah, I tend to agree this feels more like a bug fix. No need to maintain the old behavior. Thanks!