Add Latvian language support (#6749)

* Add Latvian language support

* Add empty frontend translation

* Add messages.d.ts

src/frontend/.linguirc

@@ -17,6 +17,7 @@
         "it",
         "ja",
         "ko",
+        "lv",
         "nl",
         "no",
         "pl",

src/frontend/src/contexts/LanguageContext.tsx

@@ -34,6 +34,7 @@ export const getSupportedLanguages = (): Record<string, string> => {
     it: t`Italian`,
     ja: t`Japanese`,
     ko: t`Korean`,
+    lv: t`Latvian`,
     nl: t`Dutch`,
     no: t`Norwegian`,
     pl: t`Polish`,

src/frontend/src/locales/lv/messages.d.ts

@@ -0,0 +1,4 @@
+import { Messages } from '@lingui/core';
+          declare const messages: Messages;
+          export { messages };
+