update scopedEval to return the result

We want to use scopedEval to evaluate boolean expressions. It executes the code but doesn't return back the result unless we include 'return ...' in the body.
With this quick change it returns the result of the evaluation and works on our inline conditionals.

www/js/survey/enketo/conditionalSurveys.ts

@@ -18,7 +18,7 @@ const conditionalSurveyFunctions = {
  * @example scopedEval('console.log(foo)', { foo: 'bar' })
  */
 const scopedEval = (script: string, scope: { [k: string]: any }) =>
-  Function(...Object.keys(scope), script)(...Object.values(scope));
+  Function(...Object.keys(scope), `return ${script}`)(...Object.values(scope));
 
 // the first survey in the list that passes its condition will be returned
 export function getSurveyForTimelineEntry(