New: Use translations for days of week

Closes #8384

frontend/src/Language/useLanguageName.ts

@@ -1,4 +1,5 @@
-import { useCallback } from 'react';
+import moment from 'moment';
+import { useCallback, useEffect } from 'react';
 import useApiQuery from 'Helpers/Hooks/useApiQuery';
 
 interface LanguageResponse {
@@ -22,7 +23,11 @@ const useLanguage = () => {
 };
 
 export const useInitializeLanguage = () => {
-  useLanguage();
+  const { data } = useLanguage();
+
+  useEffect(() => {
+    moment.locale(data?.identifier);
+  }, [data]);
 };
 
 const useLanguageName = () => {

frontend/src/Utilities/Date/getRelativeDate.ts

@@ -74,7 +74,7 @@ function getRelativeDate({
 
   if (isInNextWeek(date)) {
     const dateTime = convertToTimezone(date, timeZone);
-    const day = dateTime.format('dddd');
+    const day = getDayOfWeek(dateTime.day());
 
     return includeTime ? translate('DayOfWeekAt', { day, time }) : day;
   }
@@ -88,3 +88,24 @@ function getRelativeDate({
 }
 
 export default getRelativeDate;
+
+function getDayOfWeek(dayNumber: number) {
+  switch (dayNumber) {
+    case 0:
+      return translate('Sunday');
+    case 1:
+      return translate('Monday');
+    case 2:
+      return translate('Tuesday');
+    case 3:
+      return translate('Wednesday');
+    case 4:
+      return translate('Thursday');
+    case 5:
+      return translate('Friday');
+    case 6:
+      return translate('Saturday');
+    default:
+      return '';
+  }
+}