Disable calculating winners during balloting

Calculating winners before the balloting is over is useless (results
aren't published at that point) and can lead to the wrong results since
users are still voting and results might change.

And we were showing the button to calculate winners even when a budget
had finished. However, in this case the action to calculate winners did
nothing, which resulted in administrators seeing nothing happened after
pressing the button.

app/components/admin/budgets/calculate_winners_button_component.html.erb

@@ -1,4 +1,4 @@
-<% if display_button? %>
+<% if can?(:calculate_winners, budget) %>
   <%= render Admin::ActionComponent.new(
     :calculate_winners,
     budget,
@@ -9,6 +9,7 @@
     <%= t("admin.budgets.winners.calculate") %>
   </span>
   <div class="callout warning clear">
-    <%= t("admin.budget_investments.index.cannot_calculate_winners") %>
+    <%= t("admin.budget_investments.index.cannot_calculate_winners",
+          phase: t("budgets.phase.reviewing_ballots")) %>
   </div>
 <% end %>

app/components/admin/budgets/calculate_winners_button_component.rb

@@ -1,5 +1,6 @@
 class Admin::Budgets::CalculateWinnersButtonComponent < ApplicationComponent
   attr_reader :budget, :from_investments
+  delegate :can?, to: :helpers
 
   def initialize(budget, from_investments: false)
     @budget = budget
@@ -8,10 +9,6 @@ class Admin::Budgets::CalculateWinnersButtonComponent < ApplicationComponent
 
   private
 
-    def display_button?
-      budget.balloting_or_later?
-    end
-
     def text
       if budget.investments.winners.empty?
         t("admin.budgets.winners.calculate")