Revert "Adds .js-class for specs"

The `js-` prefix (which I admit I'm not fond of) is usually used to
indicate the class is used by JavaScript files, not for using it in test
files. And in all the other similar tests, we're using the `in-favor`
class instead of the `js-in-favor` class.

This reverts commit 83fe74d53.

app/views/budgets/investments/_votes.html.erb

@@ -8,7 +8,7 @@
     <%= t("budgets.investments.investment.supports", count: investment.total_votes) %>
   </span>
 
-  <div class="in-favor js-in-favor">
+  <div class="in-favor">
     <% if user_voted_for %>
       <div class="supported callout success">
         <%= t("budgets.investments.investment.already_supported") %>

spec/system/management/budget_investments_spec.rb

@@ -277,7 +277,7 @@ describe "Budget Investments" do
       expect(page).to have_content(budget_investment.title)
 
       within("#budget-investments") do
-        find(".js-in-favor a").click
+        find("in-favor a").click
 
         expect(page).to have_content "1 support"
         expect(page).to have_content "You have already supported this investment project. Share it!"
@@ -302,7 +302,7 @@ describe "Budget Investments" do
 
       expect(page).to have_css "h1", exact_text: budget_investment.title
 
-      find(".js-in-favor a").click
+      find(".in-favor a").click
 
       expect(page).to have_content "1 support"
       expect(page).to have_content "You have already supported this investment project. Share it!"
@@ -325,7 +325,7 @@ describe "Budget Investments" do
 
       expect(page).to have_css "h1", exact_text: "Default heading investment"
 
-      accept_confirm { find(".js-in-favor a").click }
+      accept_confirm { find(".in-favor a").click }
 
       expect(page).to have_content "1 support"
       expect(page).to have_content "You have already supported this investment project. Share it!"