forms: remove import from the same package

Change-Id: Ia15b4586e183bcd24a47c1a072c4d6e8ca280e98
Reviewed-on: https://gerrit.libreoffice.org/11714
Reviewed-by: Noel Grandin <noelgrandin@gmail.com>
Tested-by: Noel Grandin <noelgrandin@gmail.com>