To reproduce
=============
- on settings upload a custom background on document layout and save it
- open document layout again and try to download the image -> Traceback
Problem
=======
when calling download method we will ask server for a record with `id=false`
which gives an error
Solution
========
download button shouldn't be visible when `record.resId == false`
opw-3138230
closesodoo/odoo#113029
X-original-commit: 2e2cdee563dd645cabe2d361489d6eb17b174a33
Signed-off-by: Aaron Bohy (aab) <aab@odoo.com>