[MM-34076] Add Plugin API User custom status (#17435)

* add missing client for custom user status

* add custom user status plugin api

* update based on feedback review

* add GetCustomStatus

* update interfaces

app/plugin_api.go

@@ -344,6 +344,18 @@ func (api *PluginAPI) SetUserStatusTimedDND(userID string, endTime int64) (*mode
 	return api.app.GetStatus(userID)
 }
 
+func (api *PluginAPI) UpdateUserCustomStatus(userID string, customStatus *model.CustomStatus) *model.AppError {
+	return api.app.SetCustomStatus(userID, customStatus)
+}
+
+func (api *PluginAPI) RemoveUserCustomStatus(userID string) *model.AppError {
+	return api.app.RemoveCustomStatus(userID)
+}
+
+func (api *PluginAPI) GetUserCustomStatus(userID string) (*model.CustomStatus, *model.AppError) {
+	return api.app.GetCustomStatus(userID)
+}
+
 func (api *PluginAPI) GetUsersInChannel(channelID, sortBy string, page, perPage int) ([]*model.User, *model.AppError) {
 	switch sortBy {
 	case model.ChannelSortByUsername: