PLT-6214 Move channel store and actions over to redux (#6235)

* Move channel store and actions over to redux

* Fix style errors

* Fix unit test

* Various fixes

* More fixes

* Revert config changes

api4/channel.go

@@ -456,11 +456,6 @@ func searchChannelsForTeam(c *Context, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	if len(props.Term) == 0 {
-		c.SetInvalidParam("term")
-		return
-	}
-
 	if !app.SessionHasPermissionToTeam(c.Session, c.Params.TeamId, model.PERMISSION_LIST_TEAM_CHANNELS) {
 		c.SetPermissionError(model.PERMISSION_LIST_TEAM_CHANNELS)
 		return