Allow disconnecting service-connector from stack component

[safoinme]

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I implemented/fixed _ to achieve _.

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[fa9r]

Great functionality, looking forward to using that 👍

Overall the implementation looks good, however I would prefer if disconnect was a separate field in the StackComponentUpdateModel since connector=None usually just means that this value was not provided and should not be updated. See comment below.

Other than that only minor issues, looks like we can merge it today 🚀

[fa9r]

Currently, if any value in an update model is None, it means that this value was not provided and should not be updated. So I think the current design is breaking this convention since connector=None now disconnects the existing connector and thereby leads to updates.

Instead, I would suggest to add disconnect as a field of StackComponentUpdateModel explicitly and then use this here instead:

Suggested change

	else:
	existing_component.connector = None
	existing_component.connector_resource_id = None
	elif component_update.disconnect:
	existing_component.connector = None
	existing_component.connector_resource_id = None

[stefannica]

I think it's fine as it is, because this immediately fixes the UI as well. The alternative also requires dashboard changes. If it helps, this is the same approach used for service connector updates: some update fields are "special", in the sense that if set to None or omitted from the update request, they are interpreted as a value removal rather than a value omission.

[stefannica]

LGTM aside from the changes that Felix already suggested.