Show current exemption date when editing 2SV exemption

We were defaulting to showing tomorrow's date when editing a 2SV
exemption reason.

This meant an admin could unintentionally change the user's exemption
expiry date,

Changing this to show their current exemption by default.

app/views/two_step_verification_exemptions/edit.html.erb

@@ -22,7 +22,7 @@
   <div class="form-group add-top-margin">
     <label for="user_expiry_date_for_2sv_exemption">Expiry date for exemption</label>
     <div class="form-inline">
-      <%= date_select :user, :expiry_date_for_2sv_exemption, {start_year: Time.zone.today.year, selected: Time.zone.today + 1} %>
+      <%= date_select :user, :expiry_date_for_2sv_exemption, {start_year: Time.zone.today.year, default: Time.zone.today + 1, selected: @user.expiry_date_for_2sv_exemption} %>
     </div>
   </div>
   <p>All exemptions must have an expiry date. As this date approaches, this exemption will need to be reviewed.</p>

test/integration/managing_two_step_verification_test.rb

@@ -214,6 +214,12 @@ class ManagingTwoStepVerificationTest < ActionDispatch::IntegrationTest
 
             sign_in_as_and_edit_user(@super_admin, user_requiring_2sv)
             click_link("Edit reason or expiry date for 2-step verification exemption")
+
+            assert page.has_field?("Reason for 2-step verification exemption", with: "user is exempt")
+            assert page.has_field?("user_expiry_date_for_2sv_exemption_1i", with: @expiry_date.year)
+            assert page.has_field?("user_expiry_date_for_2sv_exemption_2i", with: @expiry_date.month)
+            assert page.has_field?("user_expiry_date_for_2sv_exemption_3i", with: @expiry_date.day)
+
             new_expiry_date = 1.month.from_now.to_date
             fill_in_exemption_form(@reason_for_exemption, new_expiry_date)