forms: Fix ambiguous id / value for typeahead

If a dynamic list is displayed as a typeahead box, the value, when saved,
will be confused with the corresponding ID field for the list. MySQL
supports numeric comparison between the INT id column and the textual value
column. Therefore, if a typeahead field has the value of '01 - GooGoo', then
record will match the ListItem<id=1>, regardless of which list the item is
defined for.

This patch resolves the issue by submitting the ID number of the list
selection in the HTTP form.