This updates the @valid_prefs_required decorator to also check to see

whether any consent requirements need to be decided upon by the user. If

so, they're redirected to the My Account page to provide consent. This

will happen any time there's a consent requirement that the user has not

decided upon.
Many of the views in Review Board didn't have this decorator (or its

mixin equivalent) applied, so I've also gone through and added it to any

pages that were relevant.

Unit tests pass.
Manually tested with the global option enabled/disabled.
Manually tested with no consent options provided, only some provided,

and all provided.