fix adminhtml file attribute edit form

fixes #11252

not sure why this line was introduced as the only place this function is used seems to be here:
https://github.com/magento/magento2/blob/55e9a5cc9d88ef785f39217e96da02b1cdf3e247/app/code/Magento/Customer/Model/FileUploader.php#L110
and it uses 'path' key right after call.

Author: fsw

app/code/Magento/Customer/Model/FileProcessor.php

@@ -181,7 +181,6 @@ public function saveTemporaryFile($fileId)
         );
 
         $result = $uploader->save($path);
-        unset($result['path']);
         if (!$result) {
             throw new \Magento\Framework\Exception\LocalizedException(
                 __('File can not be saved to the destination folder.')