Revert "[MM-8497] Ability to set Do Not Disturb for a specified period of time (#16067)" (#17657)

This reverts commit 77d42568f9.

app/plugin_api.go

@@ -317,14 +317,6 @@ func (api *PluginAPI) UpdateUserStatus(userID, status string) (*model.Status, *m
 	return api.app.GetStatus(userID)
 }
 
-func (api *PluginAPI) SetUserStatusTimedDND(userID string, endTime int64) (*model.Status, *model.AppError) {
-	// read-after-write bug which will fail if there are replicas.
-	// it works for now because we have a cache in between.
-	// FIXME: make SetStatusDoNotDisturbTimed return updated status
-	api.app.SetStatusDoNotDisturbTimed(userID, endTime)
-	return api.app.GetStatus(userID)
-}
-
 func (api *PluginAPI) GetUsersInChannel(channelID, sortBy string, page, perPage int) ([]*model.User, *model.AppError) {
 	switch sortBy {
 	case model.CHANNEL_SORT_BY_USERNAME: