Save channel included categories and expose channel version history

[Jakoma02]

Summary

This PR includes the list of included categories and licenses in the Channel published_data field and adds a get_published_data channel action to query the published data.

Detailed changes:

• The fill_published_fields method was modified to include the included_licenses and included_categories fields in published_data on channel publish
• The get_published_data action was added to ChannelViewSet
• Tests were added to verify the functionality

No manual testing other than designing the tests and checking that they pass was done.

References

Closes #5169.

Reviewer guidance

The get_published_data is available for users with edit permissions for the given channel, it should be checked that this matches the expectation.

[AlexVelezLl]

LGTM! Code changes makes sense, unit tests give confidence on the changes, and manual QA passes. Just found a potentially unintentional change, after we revert this change, we can proceed with the merge :).

[AlexVelezLl]

Was there any motivation to change this line? Seems like an unintentional change.

[Jakoma02]

Oh no, this was not intentional... this change was suggested to me by Copilot code review, I did not realize it was suggesting changes for a line I haven't even touched. Also, I remember checking that HttpResponse is indeed not returned from the function, I must have been blind 🙈 On the other hand, I in fact had the types wrong in the function I did write, and Copilot did not catch that 🤷 It definitely seems I need to be more careful with this in the future, thanks for catching this! Fixed in 73b72be.

[Jakoma02]

Or maybe Copilot was right and discovered the actual mistake, and I just messed up when fixing it... I'm not 100% sure right now

[AlexVelezLl]

Thanks @Jakoma02! LGTM!