Add ability to turn off Error messages when Includes are not viewable due to permissions

As an Admin I would like the ability to turn off the error message when an Include is not rendered due to access.

Use case:
Using Confluence as a KB for JSD and want to have some information visible to agents only on the same page as the customer documentation. When we use the built-in Except Include macro, if the page is not visible by the customer, it shows an error:

• create Page A and restrict it so only yourself and users in the 'administrators' group can view and edit it

• put a Multiexcerpt on Page A containing simple content

• create Page B, open to viewing by any logged in user

• put a Multexcerpt Include on Page B to include the excerpt from Page A

• verify a user in 'administrators' can see the included content when they access Page B

• verify a user who is NOT yourself and NOT in the group 'administrators' cannot see the included content when they access Page B. Verify that they see the error message.