fix(multi-dropzone): Fix MultiDropzone not uploading when clicking on label

[diogomateus]

What this PR does

If clicking on the Choose file or drag & drop label on a safari browser, the upload isn't triggered.

Behaviour can be reproduced here.

This seems to be caused by the fact that we are triggering our own id while react-dropzone creates its own input reference inside.

Checklist:

• I reviewed my own code
• The changes align with the designs I received
  Or give a reason why this does not apply:
• I have attached screenshot(s), video(s) or gif(s) showing that the solution is working as expected
  Or give a reason why this does not apply:
• I have updated the task(s) status on Linear
• All new media is optimized (images, gifs, videos)

Browser support

My code works in the following browsers:

• Firefox
• Chrome
• Safari
• Edge