Update breadcrumb markup
Update breadcrumb markup

Remove additional nav element wrapping the ordered list.
Remove any classes which aren’t required - header-context, group.

joelanman/govuk_elements,joelanman/govuk_elements,alphagov/govuk_elements,alphagov/govuk_elements,TFOH/govuk_elements,alphagov/govuk_elements,alphagov/govuk_elements,TFOH/govuk_elements,gavboulton/govuk_elements,gavboulton/govuk_elements,gavboulton/govuk_elements,gavboulton/govuk_elements