Be able to type the channel name in inbox view to pick the channel

Kam: Right now we have to do a drop down and find the specific channel which can be a bit annoying. I want to make it really easy for someone to choose a channel to post in inbox view. We can have some sort of combination of dropdown and typing to search.

There is two use cases. One is frequent channels. Maybe the sorting should be based on the last channel you posted to. (Probably a separate issue)

Then for infrequent channels you can start typing and it could auto complete search based on the text