Default channel per inbox

Currently, each teammate can configure their default channel, and this will apply to every inbox. However, teammates may need the default channel to change depending on which inbox the conversation belongs to or is currently being viewed. We can solve this need by allowing a default channel to be selected for each inbox.

Open questions:

• Does this remain as a user preference for each teammate to select per inbox, or do we allow admins to define the default channel for each inbox?

• If the latter, does it replace or overwrite the existing user preference?