title: ir.attachment in diferent model can view diferent ways
body: <p>I work with file storage module and need to upload files to module.
  In my definition i use </p>
  
  <pre><code>class TestClass(models.TransientModel):
  _name = "module_name.test_class"
  
    attachment_id = fields.Many2one(
      comodel_name='ir.attachment',
      string="newFileVersion",
      index=True,
      copy=False
   )
  </code></pre>
  
  <p>When i use in xml</p>
  
  <pre><code>&lt;field name="attachment_id"/&gt;
  </code></pre>
  
  <p>it shows input dropdown item with alredy loaded in DB files, but I need to choose files from my local computer. What I did wrong. (Sorry for bad english)</p>