Remove unused arrayToString function

src/main/webapp/app/exercise/exercise-details/exercise-metadata/exercise-metadata.component.ts

@@ -37,23 +37,6 @@ export class ExerciseMetadataComponent implements OnInit, OnDestroy {
     return "<a class='text-dark' href='mailto:" + person.email + "'>" + person.name + ', ' + person.affiliation + '</a>';
   }
 
-  public arrayToString(array: string[]): string {
-    let result = '';
-    let i = 1;
-    array.forEach(element => {
-      if (array.length > 1 && array.length !== i) {
-        result += element + ', ';
-      } else {
-        result += element;
-      }
-      if (i % 5 === 0) {
-        result += '<br>';
-      }
-      i++;
-    });
-    return result;
-  }
-
   ngOnDestroy(): void {
     if (this.authSubscription) {
       this.authSubscription.unsubscribe();