Use request.CTX instead of *request.Context (#24877)

* Use request.CTX instead of *request.Context

* Fix tests

server/channels/app/slashcommands/command_leave.go

@@ -34,7 +34,7 @@ func (*LeaveProvider) GetCommand(a *app.App, T i18n.TranslateFunc) *model.Comman
 	}
 }
 
-func (*LeaveProvider) DoCommand(a *app.App, c *request.Context, args *model.CommandArgs, message string) *model.CommandResponse {
+func (*LeaveProvider) DoCommand(a *app.App, c request.CTX, args *model.CommandArgs, message string) *model.CommandResponse {
 	var channel *model.Channel
 	var noChannelErr *model.AppError
 	if channel, noChannelErr = a.GetChannel(c, args.ChannelId); noChannelErr != nil {