Keep channel properties in thing updates

[J-N-K]

Fixes #3610

[lolodomo]

Thank you @J-N-K .

I have the feeling you could also fix the problem for label/description with that code ?

        if (label != null) {
            channelBuilder.withLabel(Objects.requireNonNull(label));
        } else {
            channelBuilder.withLabel(oldChannel.getLabel());
        }

        if (description != null) {
            channelBuilder.withDescription(Objects.requireNonNull(description));
        } else {
            channelBuilder.withDescription(oldChannel.getDescription());
        }

[J-N-K]

No. That would most probably be wrong, because the new channel would inherit from the old one instead of the channel-type.

[lolodomo]

No. That would most probably be wrong, because the new channel would inherit from the old one instead of the channel-type.

Oh yes, you're right but that is exactly the same thing for properties, we need to find properties from the new channel, not the old one, that is the use case from @alexf2015, he added channel properties.

[J-N-K]

We could probably add a new section similar to label that adds new properties.

[kaikreuzer]

@alexf2015 You mentioned here that you don't think that this PR fixes your issue. Shall it be merged nonetheless or do you expect further changes?

[kaikreuzer]

Thanks!