Implement empty translation check. (#15364)

Makefile

@@ -232,6 +232,10 @@ i18n-extract: ## Extract strings for translation from the source code
 	$(GO) get -modfile=go.tools.mod github.com/mattermost/mattermost-utilities/mmgotool
 	$(GOBIN)/mmgotool i18n extract --portal-dir=""
 
+i18n-check: ## Exit on empty translation strings except in english base file
+	$(GO) get -modfile=go.tools.mod github.com/mattermost/mattermost-utilities/mmgotool
+	$(GOBIN)/mmgotool i18n clean-empty --portal-dir="" --check
+
 store-mocks: ## Creates mock files.
 	$(GO) get -modfile=go.tools.mod github.com/vektra/mockery/...
 	$(GOBIN)/mockery -dir store -all -output store/storetest/mocks -note 'Regenerate this file using `make store-mocks`.'