Panels scss lint fixes
Panels scss lint fixes

- Merge rule `.panel-indent legend`
- Merge rule `.panel-indent .form-group:last-child`

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