Make sure handleUploadError exists

src/plugins/Tus10.js

@@ -119,7 +119,10 @@ export default class Tus10 extends Plugin {
           return resolve('Success')
         }
         this.core.log(`Remote upload of file '${file.name}' failed`)
-        file.acquiredBy.handleUploadError(res)
+
+        if (file.acquiredBy.handleUploadError) {
+          file.acquiredBy.handleUploadError(res)
+        }
 
         return reject(new Error('Error: ' + res.statusText))
       })