[BUGFIX] Cast pageId to integer before storing a preset in EXT:impexp

[BUGFIX] Cast pageId to integer before storing a preset in EXT:impexp

When storing a export preset in EXT:impexp no pageId is being set when
exporting a single table or record instead of a pagetree branch. Cast
the value for the pageId to integer to avoid MySQL strict mode errors.

Resolves: #72773
Releases: master, 7.6
Change-Id: Id8af258f96680201adaebeb82f488818a3013720
Reviewed-on: https://review.typo3.org/46027
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>