[accessibility] remove links from activity filter

labels should not be implemented as links

app/views/activities/index.html.erb

@@ -44,7 +44,7 @@
 <h3><%= l(:label_activity) %></h3>
 <p><% @activity.event_types.each do |t| %>
 <%= check_box_tag "show_#{t}", 1, @activity.scope.include?(t) %>
-<label for="show_<%=t%>"><%= link_to(l("label_#{t.singularize}_plural"), {"show_#{t}" => 1, :user_id => params[:user_id]})%></label>
+<label for="show_<%=t%>"><%=l("label_#{t.singularize}_plural")%></label>
 <br />
 <% end %></p>
 <% if @project && @project.descendants.active.any? %>