Use correct query for loading state

aleksis/apps/alsijil/frontend/components/coursebook/statistics/StatisticsForPersonCard.vue

 <template>
   <v-card>
-    <v-skeleton-loader v-if="$apollo.loading" type="card-heading" />
+    <v-skeleton-loader
+      v-if="$apollo.queries.statistics.loading"
+      type="card-heading"
+    />
     <v-card-title v-else-if="compact">
       {{ $t("alsijil.coursebook.statistics.person_compact.title") }}
       <v-spacer />
@@ -26,12 +29,12 @@
           style="grid-area: tardinesses"
           :tardiness-sum="statistics.tardinessSum"
           :tardiness-count="statistics.tardinessCount"
-          :loading="$apollo.loading"
+          :loading="$apollo.queries.statistics.loading"
         />
         <statistics-extra-marks-card
           style="grid-area: extra_marks"
           :extra-marks="statistics.extraMarks"
-          :loading="$apollo.loading"
+          :loading="$apollo.queries.statistics.loading"
         />
       </div>
     </v-card-text>