Do not show cancel button on webforms

Please review patch.

@StryKaizer,

The patch provided by @chaitanyadessai works well and successfully removes the cancel button from all webforms. However, I believe the module is intended to display the cancel button on all types of forms, so there's no need to remove the button from webforms.

This should be worked up in a way that there is a config option to enable/disable the cancel on webforms too.