Show translation files parsing errors on Designer menu

Since NXS-6745, saving is still possible when a translation json file has errors (it has been edited via direct git access for example).

But, when there are such errors, the labels that need to be added automatically (for page providers for example) are just not added. There should be a way for the user to see there are errors in the translation files without opening them. A small badge on the corresponding menu item like what is used for validation errors and warning on Modeler side could be a solution.