catch more errors if something catastrophic happens to encrypted data

src/views/IdentitySwitcherView.vue

@@ -170,6 +170,7 @@ export default class IdentitySwitcherView extends Vue {
         title: "Delete Identity?",
         text: "Are you sure you want to erase this identity? (There is no undo. You may want to select it and back it up just in case.)",
         onYes: async () => {
+          // one of the few times we use accountsDBPromise directly; try to avoid more usage
           const accountsDB = await accountsDBPromise;
           await accountsDB.accounts.delete(id);
           this.otherIdentities = this.otherIdentities.filter(