Import notification banner macro

Import the notification banner so that users can include it in the prototype kit without needing to import it themselves, as we tell them to do in the ‘Getting Started’ documentation in the Design System[1]

[1]: https://design-system.service.gov.uk/get-started/prototyping/#:~:text=When%20using%20Nunjucks%20macros%20in%20the%20Prototype%20Kit%20leave%20out%20the%20first%20line%20that%20starts%20with%20%7B%25%20from%20....

app/views/layout.html

@@ -3,31 +3,32 @@
 
 {% extends "govuk/template.njk" %}
 
-{% from "govuk/components/accordion/macro.njk"        import govukAccordion %}
-{% from "govuk/components/back-link/macro.njk"        import govukBackLink %}
-{% from "govuk/components/breadcrumbs/macro.njk"      import govukBreadcrumbs %}
-{% from "govuk/components/button/macro.njk"           import govukButton %}
-{% from "govuk/components/character-count/macro.njk"  import govukCharacterCount %}
-{% from "govuk/components/checkboxes/macro.njk"       import govukCheckboxes %}
-{% from "govuk/components/date-input/macro.njk"       import govukDateInput %}
-{% from "govuk/components/details/macro.njk"          import govukDetails %}
-{% from "govuk/components/error-message/macro.njk"    import govukErrorMessage %}
-{% from "govuk/components/error-summary/macro.njk"    import govukErrorSummary %}
-{% from "govuk/components/fieldset/macro.njk"         import govukFieldset %}
-{% from "govuk/components/file-upload/macro.njk"      import govukFileUpload %}
-{% from "govuk/components/input/macro.njk"            import govukInput %}
-{% from "govuk/components/inset-text/macro.njk"       import govukInsetText %}
-{% from "govuk/components/panel/macro.njk"            import govukPanel %}
-{% from "govuk/components/phase-banner/macro.njk"     import govukPhaseBanner %}
-{% from "govuk/components/radios/macro.njk"           import govukRadios %}
-{% from "govuk/components/select/macro.njk"           import govukSelect %}
-{% from "govuk/components/skip-link/macro.njk"        import govukSkipLink %}
-{% from "govuk/components/summary-list/macro.njk"     import govukSummaryList %}
-{% from "govuk/components/table/macro.njk"            import govukTable %}
-{% from "govuk/components/tabs/macro.njk"             import govukTabs %}
-{% from "govuk/components/tag/macro.njk"              import govukTag %}
-{% from "govuk/components/textarea/macro.njk"         import govukTextarea %}
-{% from "govuk/components/warning-text/macro.njk"     import govukWarningText %}
+{% from "govuk/components/accordion/macro.njk"           import govukAccordion %}
+{% from "govuk/components/back-link/macro.njk"           import govukBackLink %}
+{% from "govuk/components/breadcrumbs/macro.njk"         import govukBreadcrumbs %}
+{% from "govuk/components/button/macro.njk"              import govukButton %}
+{% from "govuk/components/character-count/macro.njk"     import govukCharacterCount %}
+{% from "govuk/components/checkboxes/macro.njk"          import govukCheckboxes %}
+{% from "govuk/components/date-input/macro.njk"          import govukDateInput %}
+{% from "govuk/components/details/macro.njk"             import govukDetails %}
+{% from "govuk/components/error-message/macro.njk"       import govukErrorMessage %}
+{% from "govuk/components/error-summary/macro.njk"       import govukErrorSummary %}
+{% from "govuk/components/fieldset/macro.njk"            import govukFieldset %}
+{% from "govuk/components/file-upload/macro.njk"         import govukFileUpload %}
+{% from "govuk/components/input/macro.njk"               import govukInput %}
+{% from "govuk/components/inset-text/macro.njk"          import govukInsetText %}
+{% from "govuk/components/notification-banner/macro.njk" import govukNotificationBanner %}
+{% from "govuk/components/panel/macro.njk"               import govukPanel %}
+{% from "govuk/components/phase-banner/macro.njk"        import govukPhaseBanner %}
+{% from "govuk/components/radios/macro.njk"              import govukRadios %}
+{% from "govuk/components/select/macro.njk"              import govukSelect %}
+{% from "govuk/components/skip-link/macro.njk"           import govukSkipLink %}
+{% from "govuk/components/summary-list/macro.njk"        import govukSummaryList %}
+{% from "govuk/components/table/macro.njk"               import govukTable %}
+{% from "govuk/components/tabs/macro.njk"                import govukTabs %}
+{% from "govuk/components/tag/macro.njk"                 import govukTag %}
+{% from "govuk/components/textarea/macro.njk"            import govukTextarea %}
+{% from "govuk/components/warning-text/macro.njk"        import govukWarningText %}
 
 {% block head %}
   {% include "includes/head.html" %}