fdo#74160 firebird XParameters::setString truncate to 65535 characters

as opposed to 17 characters

Change-Id: I65c82243946c22eee0f033977b1cd0c5a84d226b
Reviewed-on: https://gerrit.libreoffice.org/7745
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>