The export feature already exported the whole domain when the
thead selector checkbox was checked (unlike all other actions
which were executed on the current page only).
Following the new selection feature, this commit uniformizes the
behavior of the export with other actions: if the page is selected,
only the records on that page are exported. To export all records
matching the current domain, the user has to click on the 'Select
all' link in the control panel.
Part of task 2185145
Aaron Bohy
9755e8875b