Extract methods in votes components

This way we can make the view code a bit easier to read.

We're also changing the order of the conditions a little bit so we only
check for the presence of a current user once.

To make sure we aren't breaking anything with these changes, we're
adding some tests. We're also replacing one system test checking content
with a component test, since component tests are much faster.

app/components/legislation/proposals/votes_component.rb

@@ -5,4 +5,18 @@ class Legislation::Proposals::VotesComponent < ApplicationComponent
   def initialize(proposal)
     @proposal = proposal
   end
+
+  private
+
+    def voted_classes
+      @voted_classes ||= css_classes_for_vote(proposal)
+    end
+
+    def can_vote?
+      proposal.votable_by?(current_user)
+    end
+
+    def organization?
+      current_user&.organization?
+    end
 end