Fixed issue with logic editor in the application builder

Dear users,

We discovered an issue with the expression editor that is now fixed. This
does not affect any existing applications, only applications that have been
using the logical expression editor recently.

For approximately the past fourteen hours, if you used the expression
editor to drag a choice from a multiple choice question into the a logical
expression, the value “null” would appear instead of the correct value of
that choice.

This should now be fixed. Apologies for any inconvenience this caused!