fix problem clicking on offer-delivery, plus some other hardening and phrasing

src/views/IdentitySwitcherView.vue

@@ -94,7 +94,7 @@
     <a
       href="#"
       class="block w-full text-center text-md uppercase bg-gradient-to-b from-slate-400 to-slate-700 shadow-[inset_0_-1px_0_0_rgba(0,0,0,0.5)] text-white px-1.5 py-2 rounded-md mb-8"
-      @click="switchAccount('0')"
+      @click="switchAccount(undefined)"
     >
       No Identity
     </a>
@@ -164,10 +164,6 @@ export default class IdentitySwitcherView extends Vue {
   }
 
   async switchAccount(did?: string) {
-    // 0 means none
-    if (did === "0") {
-      did = undefined;
-    }
     await databaseUtil.updateDefaultSettings({ activeDid: did });
     if (USE_DEXIE_DB) {
       await db.open();