Fix header navigation styles to be compatible with nhsuk-frontend v9.4.x

Author: paulrobertlloyd

app/assets/stylesheets/_header.scss

@@ -9,11 +9,19 @@
 }
 
 .app-header__navigation-item--current {
-  box-shadow: inset 0 ($nhsuk-focus-width * -1) $nhsuk-border-color;
+  .nhsuk-header__navigation-link {
+    border-bottom-color: $nhsuk-border-color;
+  }
+
   .nhsuk-header__drop-down & {
     box-shadow: inset $nhsuk-focus-width 0 $nhsuk-link-color;
+
+    .nhsuk-header__navigation-link {
+      border-bottom-color: transparent;
+    }
   }
 }
+
 .app-header__navigation-item--with-count {
   .app-count {
     @include nhsuk-font(14, $line-height: 1);

app/assets/stylesheets/_overrides.scss

@@ -1,8 +1,8 @@
 // `$nhsuk-page-width` isn’t globally editable, so need to apply manually
 .app-signed-in {
   .nhsuk-width-container,
-  .nhsuk-header__navigation-list,
-  .nhsuk-header__container {
+  .nhsuk-header__container,
+  .nhsuk-navigation {
     max-width: $app-page-width;
 
     @include govuk-media-query($from: desktop) {