Update the offer email to include "mandatory checks" information

app/views/candidate_mailer/new_offer_made.text.erb

@@ -8,10 +8,18 @@ Congratulations! You have an offer from <%= @provider_name %> to study <%= @cour
  - <%= condition.text %>
 <% end %>
 
-Contact <%= @provider_name %> if you have any questions about this.
-
 <% if @show_deadline_reminder %>
   If you want to accept this offer, you must do so by <%= I18n.l(CycleTimetable.decline_by_default_date.to_date, format: :no_year) %>. If you have not responded by then, the offer will be automatically declined on your behalf.
 <% end %>
 
+You will have to pass essential checks before you can start your training.
+
+These are:
+  - An enhanced disclosure and barring service (DBS) check. This is a criminal records check to make sure it is safe for you to work with children. If you are from outside of the UK and Ireland then the training provider will request a criminal records check from your home country.
+  - A fitness to train to teach check. These are questions to check your ability to meet teaching standards, both physically and mentally.
+
+The training provider will usually pay for the criminal records checks.
+
+Contact <%= @provider_name %> if you have any questions about this.
+
 [Sign into your account to respond to your offer](<%= candidate_magic_link(@application_form.candidate) %>).

spec/mailers/candidate_mailer_spec.rb

@@ -670,7 +670,9 @@
       )]
     end
 
-    it 'renders deadline reminder text' do
+    it 'renders essential checks and deadline reminder text' do
+      expect(email.body).to include 'An enhanced disclosure and barring service (DBS) check. This is a criminal records check to make sure it is safe for you to work with children. If you are from outside of the UK and Ireland then the training provider will request a criminal records check from your home country.'
+      expect(email.body).to include 'A fitness to train to teach check. These are questions to check your ability to meet teaching standards, both physically and mentally.'
       expect(email.body).to include "If you want to accept this offer, you must do so by #{I18n.l(CycleTimetable.decline_by_default_date.to_date, format: :no_year)}. If you have not responded by then, the offer will be automatically declined on your behalf."
     end
   end