Address code style concerns

ee/app/assets/javascripts/ci_minutes_usage/components/app.vue

@@ -23,7 +23,7 @@ export default {
   },
   computed: {
     minutesUsageDataByMonth() {
-      return this?.ciMinutesUsage.map((cur) => [cur.month, cur.minutes]);
+      return this.ciMinutesUsage.map((cur) => [cur.month, cur.minutes]);
     },
   },
 };

ee/app/assets/javascripts/ci_minutes_usage/components/minutes_usage_project_chart.vue

@@ -83,7 +83,7 @@ export default {
           v-for="(month, index) in months"
           :key="index"
           :is-checked="selectedMonth === month"
-          :is-check-item="true"
+          is-check-item
           @click="changeSelectedMonth(month)"
         >
           {{ month }}