forms: Preserve data for help topic fields

This patch fixes a glitch in the dynamic forms processing system preventing
the validation and capture of data for help topic custom fields. Now the
`$vars` managed inside of `Ticket::create` is connected directly to the
`DynamicFormEntry` created for the data rather than using the magical
connection to `$_POST`.
forms: Fix save of user profile data
forms: Phone numbers with no digits = invalid

Previously, the characters would be removed and the data would be considered
empty which would bypass validation and clear the phone number on save
rather than triggering a validation error.
Merge pull request #1105 from greezybacon/issue/1083

forms: Preserve data for help topic fields

Reviewed-By: Peter Rotich <peter@osticket.com>