Move travel advice styles

- Remove bespoke "get involved" CSS from Application, this is not needed as all styling is coming from the gem and Design System

- There appeared to be some "travel-advice" styling in the top-level application.css - this isn't the right place for this, so this has been moved to travel-advice.css

app/assets/stylesheets/application.scss

@@ -95,24 +95,3 @@ $govuk-new-link-styles: true;
 @import 'views/answer';
 @import 'views/help-page';
 @import 'views/guide';
-// @import 'views/get-involved';
-
-.travel-advice-notice {
-  background-color: govuk-colour("light-grey");
-  border: 1px solid $govuk-border-colour;
-  margin-bottom: govuk-spacing(7);
-  position: relative;
-}
-
-.travel-advice-notice__header {
-  padding: govuk-spacing(4) govuk-spacing(4) 0 govuk-spacing(3);
-}
-
-.travel-advice-notice__content {
-  margin-top: - govuk-spacing(3);
-  padding: 0 govuk-spacing(4) 0 govuk-spacing(9);
-}
-
-.travel-advice-notice__icon {
-  margin-left: govuk-spacing(3);
-}

app/assets/stylesheets/views/_travel-advice.scss

@@ -23,3 +23,23 @@
   display: block;
   margin-bottom: govuk-spacing(2);
 }
+
+.travel-advice-notice {
+  background-color: govuk-colour("light-grey");
+  border: 1px solid $govuk-border-colour;
+  margin-bottom: govuk-spacing(7);
+  position: relative;
+}
+
+.travel-advice-notice__header {
+  padding: govuk-spacing(4) govuk-spacing(4) 0 govuk-spacing(3);
+}
+
+.travel-advice-notice__content {
+  margin-top: - govuk-spacing(3);
+  padding: 0 govuk-spacing(4) 0 govuk-spacing(9);
+}
+
+.travel-advice-notice__icon {
+  margin-left: govuk-spacing(3);
+}