Don't show an error pop up when cancelling an upload manually.

src/mami.js/eeprom/eeprom.js

@@ -69,7 +69,7 @@ const MamiEEPROM = function(endPoint, getAuthLine) {
                         return Object.freeze(body);
                     } catch(ex) {
                         if(userAborted)
-                            throw 'Upload has been cancelled by the user.';
+                            throw '';
 
                         console.error(ex);
                         throw ex;

src/mami.js/main.js

@@ -784,7 +784,7 @@ const MamiInit = async args => {
             if(settings.get('eepromAutoInsert'))
                 entry.clickOption('insert');
         } catch(ex) {
-            if(!ex.aborted) {
+            if(ex !== '') {
                 console.error(ex);
                 ctx.msgbox.show({ body: ['An error occurred while trying to upload a file:', ex] });
             }