Use check circle instead of question circle for successful athena res…

…ults

src/main/webapp/app/exercises/shared/result/result.utils.ts

@@ -315,7 +315,7 @@ export const getResultIconClass = (result: Result | undefined, templateStatus: R
         }
         // result done successfuly
         if (result.successful) {
-            return faQuestionCircle;
+            return faCheckCircle;
         }
         // generating failed
         return faTimesCircle;