Refine vocabulary selection logic in VocabLessonView to prevent duplicates

- Updated the condition for adding vocabulary options to ensure that normalized vocabulary entries are checked against the exclusion set, preventing duplicates and enhancing the learning experience.

frontend/src/views/social/VocabLessonView.vue

@@ -1070,7 +1070,7 @@ export default {
         let index = 0;
         while (options.size < 4 && index < genericOptions.length) {
           const option = genericOptions[index];
-          if (!excludeSet.has(option)) {
+          if (!normalizedExcludeSet.has(this.normalizeVocab(option)) && !options.has(option)) {
             options.add(option);
           }
           index++;