Default to only showing lessons with absences

aleksis/apps/alsijil/frontend/components/coursebook/Coursebook.vue

@@ -154,7 +154,7 @@ export default {
       groups: [],
       courses: [],
       incomplete: false,
-      absencesExist: false,
+      absencesExist: true,
       ready: false,
       initDate: false,
       currentDate: "",
@@ -218,7 +218,7 @@ export default {
           this.$refs.iterator.resetDate();
           // might skip query until both set = atomic
           if (Object.hasOwn(selectedFilters, "pageType")) {
-            this.absencesExist = false;
+            this.absencesExist = true;
           }
         }
       },