DEICH-5615: Display error message if no date is given for deviating opening hours.

tjenestekatalog/src/components/EditBranches.svelte

@@ -133,6 +133,10 @@
     }
     if (branch.deviatingOpeningHours) {
       for (let i = 0; i < branch.deviatingOpeningHours.length; i++) {
+        if (!branch.deviatingOpeningHours[i].periodStart) {
+          return { error: "Ugyldig input", message: "Dato må være angitt", details: "En avvikende åpningstid mangler dato. Vennligst fyll inn en dato eller periode." }
+        }
+
         const manned = branch.deviatingOpeningHours[i].manned
         if (manned) {
           const mannedFrom = branch.deviatingOpeningHours[i].mannedFrom