Fix lowercase Russian title on the Theme settings page

[Rei-Aayanami]

In the Russian localization, the /settings/theme page header is displayed as темы with a lowercase first letter.

The settings page header uses:

<PageHeader title={t(`settings.${activeTab}.title`)} description="manageSettings" />

So for /settings/theme, it resolves to settings.theme.title.

Currently, the Russian locale contains:

"settings": {
  "theme": {
    "title": "темы"
  }
}

Expected behavior

The page title should be capitalized and singular:

Тема

Suggested fix

Update dashboard/public/statics/locales/ru.json:

- "title": "темы"
+ "title": "Тема"

Additional context

The top-level theme.title key is already translated as Тема, but the page header uses settings.theme.title, so the lowercase value is still visible on /settings/theme.

[M03ED]

fixed