chore: update interpolation syntax for i18n files (#10198)

There were two warnings showing up on new teams page

1. `errorMessage` prop was getting invalid value, this was because were
short circuting the error message using `&&`, fixed it by using ternary
operator
2. `vue-i18n` has deprecated [rails
syntax](https://vue-i18n.intlify.dev/guide/essentials/syntax#rails-i18n-format),
fixed that warning by removing `%` before `{}` for interpolation

> Note: the `vue-i18n` deprecation needs to be handled, but we can do it
later

app/javascript/dashboard/i18n/locale/de/settings.json

@@ -301,7 +301,7 @@
     "TITLE": "Rechnungen",
     "CURRENT_PLAN": {
       "TITLE": "Derzeitiger Plan",
-      "PLAN_NOTE": "Sie haben derzeit den Tarif **%{plan}** mit **%{quantity}** Lizenzen abonniert"
+      "PLAN_NOTE": "Sie haben derzeit den Tarif **{plan}** mit **{quantity}** Lizenzen abonniert"
     },
     "MANAGE_SUBSCRIPTION": {
       "TITLE": "Abonnement verwalten",