The clone block button does not generate a new instance_id #336
Description
We noticed that many blocks had the same pair (instance_id|id_shop|id_lang).
This pair is supposed to be unique.
Reversia, for example, uses it to identify blocks to be translated.
The duplication should generate a new instance_id.
How to reproduce:
1 Create a block, observe its instance_id
2 Clone the block, observe its instance_id
