Resolve "Absence dialog doesn't work"

Closes #327 (closed)

aleksis/apps/alsijil/frontend/components/coursebook/absences/AbsenceCreationDialog.vue

@@ -161,14 +161,17 @@ export default {
           reason: this.absenceReason,
         },
         (storedDocumentations, incomingStatuses) => {
-          const documentation = storedDocumentations.find(
-            (doc) => doc.id === this.documentation.id,
-          );
-
           incomingStatuses.forEach((newStatus) => {
+            const documentation = storedDocumentations.find(
+              (doc) => doc.id === newStatus.relatedDocumentation.id,
+            );
+            if (!documentation) {
+              return;
+            }
             const participationStatus = documentation.participations.find(
               (part) => part.id === newStatus.id,
             );
+
             participationStatus.absenceReason = newStatus.absenceReason;
             participationStatus.isOptimistic = newStatus.isOptimistic;
           });