* Add v4 endpoint for getting the channels on a team for a user
* Implement PUT /channels/{channel_id}/patch endpoint for APIv4
* Implement POST /teams/{team_id}/channels/search endpoint for APIv4
* Update permission check
* Implement server changes for group messaging
* Majority of client-side implementation
* Some server updates
* Added new React multiselect component
* Fix style issues
* Add custom renderer for options
* Fix model test
* Update ENTER functionality for multiselect control
* Remove buttons from multiselect UI control
* Updating group messaging UI (#5524)
* Move filter controls up a component level
* Scroll with arrow keys
* Updating mobile layout for multiselect (#5534)
* Fix race condition when backspacing quickly
* Hidden or new GMs show up for regular messages
* Add overriding of number remaining text
* Add UI filtering for team if config setting set
* Add icon to channel switcher and class prop to status icon
* Minor updates per feedback
* Improving group messaging UI (#5563)
* UX changes per feedback
* Update email for group messages
* UI fixes for group messaging (#5587)
* Fix missing localization string
* Add maximum users message when adding members to GM
* Fix input clearing on Android
* Updating group messaging UI (#5603)
* Updating UI for group messaging (#5604)
* Increase Channel Purpose length to 250.
This commit increases the maxmimum length of the channel purpose field
to 250, including the database migration necessary.
It also adds a method to the Slack importer to check the lengths of
channel properties before importing, and truncate them if necessary.
Fixes#4168
* Fix database migration.
