Final lint fixes

src/js/background/backgroundLogic.js

@@ -50,6 +50,8 @@ const backgroundLogic = {
       //We cannot yet access the new cookieStoreId via this.cookieStoreId(...), so we take this from the resolved promise
       donePromise.then((identity) => {
         window.proxifiedContainers.set(identity.cookieStoreId, options.proxy);
+      }).catch(() => {
+        //Empty because this should never happen theoretically.
       });
     }
     await donePromise;

src/js/proxified-containers.js

@@ -2,7 +2,7 @@
 if (!("toJSON" in Error.prototype))
   Object.defineProperty(Error.prototype, "toJSON", {
     value: function() {
-      let alt = {};
+      const alt = {};
 
       Object.getOwnPropertyNames(this).forEach(function(key) {
         alt[key] = this[key];