Optional breadcrumb back to section summary
Optional breadcrumb back to section summary

We don't want breadcrumbs for sections for which we don't expose
their section summary pages, so this commit makes the section
summary breadcrumb contingent on `section.has_summary_page`

alphagov/digitalmarketplace-buyer-frontend,alphagov/digitalmarketplace-buyer-frontend,AusDTO/dto-digitalmarketplace-buyer-frontend,alphagov/digitalmarketplace-buyer-frontend,alphagov/digitalmarketplace-buyer-frontend,AusDTO/dto-digitalmarketplace-buyer-frontend,AusDTO/dto-digitalmarketplace-buyer-frontend,AusDTO/dto-digitalmarketplace-buyer-frontend