Make lesson quota field required & fire setting course data only on change

aleksis/apps/lesrooster/frontend/components/timebound_course_config/TimeboundCourseConfigRaster.vue

@@ -103,7 +103,8 @@ import SubjectChip from "aleksis.apps.cursus/components/SubjectChip.vue";
                       : course.lessonQuota
                   "
                   :label="$t('lesrooster.timebound_course_config.lesson_quota')"
-                  @input="
+                  :rules="$rules().required.build()"
+                  @change="
                     (event) =>
                       setCourseConfigData(course, item.subject, header, {
                         lessonQuota: event,
@@ -187,10 +188,11 @@ import { currentValidityRange as gqlCurrentValidityRange } from "../validity_ran
 import { gqlGroupsForPlanning, gqlTeachers } from "../helper.graphql";
 
 import mutateMixin from "aleksis.core/mixins/mutateMixin.js";
+import formRulesMixin from "aleksis.core/mixins/formRulesMixin";
 
 export default {
   name: "TimeboungCourseConfigRaster",
-  mixins: [mutateMixin],
+  mixins: [formRulesMixin, mutateMixin],
   data() {
     return {
       i18nKey: "lesrooster.timebound_course_config",