More #2801 Stuff

- Remove the empty string offline currency payout upon read.
  - Immediately re-write the file without the poorly-typed value.
- Remove the empty string offline currency payout upon import, before it
  actually gets added or updated.

src/backend/currency/currency-access.ts

@@ -48,7 +48,19 @@ class CurrencyAccess {
 
         logger.debug("Refreshing currency cache");
         const db = profileManager.getJsonDbInProfile("/currency/currency");
-        this._currencyCache = db.getData("/");
+
+        let issue2801 = false;
+        const cache = db.getData("/");
+        Object.keys(cache).forEach((currencyId) => {
+            if (cache[currencyId].offline === "") {
+                issue2801 = true;
+                cache[currencyId].offline = undefined;
+            }
+        });
+        if (issue2801) {
+            db.push("/", cache);
+        }
+        this._currencyCache = cache;
     }
 
     getCurrencies(): CurrencyCache {

src/gui/app/services/currency.service.js

@@ -112,6 +112,10 @@
                 return;
             }
 
+            if (currency.offline === "") {
+                currency.offline = undefined;
+            }
+
             if (service.getCurrency(currency.id)) {
                 service.updateCurrency(currency);
             } else {