Remove logos from 'exempt' organisations
user
```ruby
Organisation.where(govuk_status: 'exempt').each do |organisation|
  @logger.info "Processing #{organisation.slug}"
  if organisation.organisation_logo_type == OrganisationLogoType::CustomLogo
    organisation.organisation_logo_type = OrganisationLogoType::NoIdentity
    organisation.remove_logo = true
    unless organisation.save
      @logger.warn "  Forcing save on invalid organisation #{organisation.slug}. Errors: #{organisation.errors.full_messages}"
      organisation.save(validate: false)
    end
    @logger.info "  Removed logo from #{organisation.slug}"
  end
end
```
assistant