Update content for sending invites to clinic

This updates the content when sending invites to the clinic after a
session has been completed to clarify that we can't know if any of the
children have already booked in to the clinic.

Jira-Issue: MAV-1792

Author: thomasleese

app/views/sessions/invite_to_clinic/edit.html.erb

@@ -10,12 +10,10 @@
 <% end %>
 
 <% if @initial_invitations %>
-  <p>This school session has been completed.</p>
-
   <% if @invitations_to_send == 1 %>
-    <p>There is <%= @invitations_to_send %> child currently without clinic appointments. You can send invitations to their parents to book an appointment.</p>
+    <p><%= @invitations_to_send %> child was not vaccinated. You can send invitations to their parents to book an appointment.</p>
   <% else %>
-    <p>There are <%= @invitations_to_send %> children currently without clinic appointments. You can send invitations to their parents to book an appointment.</p>
+    <p><%= @invitations_to_send %> children were not vaccinated. You can send invitations to their parents to book an appointment.</p>
   <% end %>
 <% else %>
   <% if @invitations_to_send == 0 %>

spec/features/manage_school_sessions_spec.rb

@@ -290,9 +290,7 @@ def when_i_click_on_send_invitations
 
   def then_i_see_the_send_invitations_page
     expect(page).to have_content("Invite parents to book a clinic appointment")
-    expect(page).to have_content(
-      "There is 1 child currently without clinic appointments."
-    )
+    expect(page).to have_content("1 child was not vaccinated.")
   end
 
   alias_method :and_i_click_on_send_invitations,