[FIX] survey: access rights error when editing

The wizard 'Edit Survey' > 'Add Question' was trowing an access rights error as the id was passed as a string instead of a real id. opw 607854
[FIX] stock: return picking, pass serial number value when returning
[FIX] web: sort with undefined value

In this awesome programming language called javascript, undefined is neither bigger nor smaller than a string. Previous code was then considering undefined values equal to any string.
This fix allows to sort in a column of a o2m field and group the undefined values together.
Fixes #2346, opw 607704