Add votes_for(option) method and simplify results template

Move the summing logic from the template into the component. Introduce
a votes_for(option) method that looks up grouped partial results and
returns the total amount or 0.

app/components/admin/poll/results/question_component.html.erb

@@ -11,7 +11,7 @@
       <% question.question_options.each_with_index do |option, i| %>
         <tr id="question_<%= question.id %>_<%= i %>_result">
           <td><%= option.title %></td>
-          <td class="text-center"><%= by_answer[option.title].present? ? by_answer[option.title].sum(&:amount) : 0 %></td>
+          <td class="text-center"><%= votes_for(option) %></td>
         </tr>
       <% end %>
     </tbody>

app/components/admin/poll/results/question_component.rb

@@ -6,7 +6,14 @@ class Admin::Poll::Results::QuestionComponent < ApplicationComponent
     @partial_results = partial_results
   end
 
-  def by_answer
-    @by_answer ||= partial_results.where(question: question).group_by(&:answer)
+  def votes_for(option)
+    grouped = by_answer[option.title] || []
+    grouped.sum(&:amount)
   end
+
+  private
+
+    def by_answer
+      @by_answer ||= partial_results.where(question: question).group_by(&:answer)
+    end
 end