Fix export if never wish on a banner category

src/functions/export.js

@@ -147,6 +147,8 @@ async function addWishHistory(workbook, icons) {
       bold: true,
     };
 
+    if (data === null) continue;
+
     let groupCount = 0;
     let lastTime = 0;
     let lastBanner = '';

src/functions/wish.js

@@ -75,7 +75,11 @@ export function process(id) {
     };
   });
 
-  const { pullData } = readLocalData(path);
+  const data = readLocalData(path);
+
+  if (data === null) return null;
+
+  const pullData = data.pullData;
 
   const currentPulls = [];
   const allLegendary = [];