Update collection recursive extract and populating nested fieldsets

Appending the child object to the child fieldset instead the parent one. Setting values of child fieldset as the correct extract
Merge branch 'hotfix/5903'

Close #5903
Merge pull request #5502 from ltouro/patch-1

Update collection recursive extract and populating nested fieldsets

Conflicts:
	library/Zend/Form/Element/Collection.php
[#5502] Added test from #5495

- Unit test passes now, meaning we can close both issues.
Merge branch 'hotfix/5502' into develop

Forward port #5502