Add validation for ServerNames pattern field in translation.json

ui/public/i18n/en/translation.json

@@ -77,6 +77,7 @@
     "Edit_Virtualhosts":"Edit virtual host {name}",
     "title": "Virtual hosts",
     "ServerNames_format": "Domain name not allowed : {error}",
+    "ServerNames_pattern": "Must be a valid fully qualified domain name: : {error}",
     "type_to_confirm": "Type <strong>{name}</strong> to confirm deletion",
     "delete_virtualhosts_confirm": "Delete virtual host <strong>{name}</strong>? All data will be deleted. This action is <strong>NOT</strong> reversible",
     "sftpgo_url": "SFTPGo WebClient",