[BUGFIX] Suggest wizard for select element does not work when maxitems = 1

Problem: When selecting an item in the suggest wizard, a js error is
raised and the select element is not updated.
Solution: The value provided by FormEngineSuggest may be an integer.
Make it a string before applying a match function.

Resolves: #70238
Releases: master
Change-Id: I9e1944d1def442a36e17980df8696c7f6078747e
Reviewed-on: http://review.typo3.org/43672


Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>