Prevent selecting an unsupported language

In case no language had been selected yet and the detected browser language is not supported, the selection was set to undefined instead of showing the default language

src/screens/Settings.tsx

@@ -40,7 +40,7 @@ import { NumberSetting } from '@/components/settings/NumberSetting.tsx';
 import { requestManager } from '@/lib/requests/RequestManager.ts';
 import { makeToast } from '@/components/util/Toast.tsx';
 import { Select } from '@/components/atoms/Select.tsx';
-import { i18nResources } from '@/i18n';
+import { I18nResourceCode, i18nResources } from '@/i18n';
 
 export function Settings() {
     const { t, i18n } = useTranslation();
@@ -147,7 +147,7 @@ export function Settings() {
                     }
                 />
                 <Select
-                    value={i18n.language}
+                    value={i18nResources.includes(i18n.language as I18nResourceCode) ? i18n.language : 'en'}
                     onChange={({ target: { value: language } }) => i18n.changeLanguage(language)}
                 >
                     {i18nResources.map((language) => (