Simplify "check all/none" buttons layout

The float property was removed in commit b71c61e40, but then it was
added again in commit 4a6313fed.

It might have been necessary to do so back then because we had a
`select` field instead of the links to set the order, but now, instead
of making them float on the left and then make the next element clear
the floats, we can do nothing and obtain the same results.

app/assets/stylesheets/check_all_none.scss

@@ -1,5 +1,4 @@
 .check-all-none {
-  float: $global-left;
   list-style-type: none;
   margin-#{$global-left}: 0;
 

app/views/moderation/budgets/investments/index.html.erb

@@ -1,5 +1,5 @@
 <%= render Moderation::Shared::IndexComponent.new(@budget_investments) do %>
-  <table class="clear">
+  <table>
     <thead>
       <tr>
         <th><%= t("moderation.budget_investments.index.headers.budget_investment") %></th>

app/views/moderation/comments/index.html.erb

@@ -1,5 +1,5 @@
 <%= render Moderation::Shared::IndexComponent.new(@comments) do %>
-  <table class="clear">
+  <table>
     <thead>
       <tr>
         <th><%= t("moderation.comments.index.headers.comment") %></th>

app/views/moderation/debates/index.html.erb

@@ -1,5 +1,5 @@
 <%= render Moderation::Shared::IndexComponent.new(@debates) do %>
-  <table class="clear">
+  <table>
     <thead>
       <tr>
         <th><%= t("moderation.debates.index.headers.debate") %></th>

app/views/moderation/proposal_notifications/index.html.erb

@@ -1,5 +1,5 @@
 <%= render Moderation::Shared::IndexComponent.new(@proposal_notifications) do %>
-  <table class="clear">
+  <table>
     <thead>
       <tr>
         <th><%= t("moderation.proposal_notifications.index.headers.proposal_notification") %></th>

app/views/moderation/proposals/index.html.erb

@@ -1,5 +1,5 @@
 <%= render Moderation::Shared::IndexComponent.new(@proposals) do %>
-  <table class="clear">
+  <table>
     <thead>
       <tr>
         <th><%= t("moderation.proposals.index.headers.proposal") %></th>