Fix display of unfeasibility explanation

We were missing a check to make sure valuation had finished before
displaying the unfeasibility explanation

app/models/budget/investment.rb

@@ -298,6 +298,10 @@ class Budget
       should_show_price? && price_explanation.present?
     end
 
+    def should_show_unfeasibility_explanation?
+      unfeasible? && valuation_finished? && unfeasibility_explanation.present?
+    end
+
     def formatted_price
       budget.formatted_amount(price)
     end