message: DRY up registries navbar
diff: >
  <nav.container>
  <nav.section data-test-left>
  - {{#if this.brand.currentBrand}}
  - <OsfLink
  - data-test-brand
  - data-analytics-name='Brand'
  - @route='home'
  - local-class='Logo'
  - aria-label={{t 'navbar.go_home'}}
  - />
  - {{else}}
  - {{! Left Side (Band, Service Dropdown) }}
  <OsfLink
  data-test-brand
  data-analytics-name='Brand'
  aria-label={{t 'navbar.go_home'}}
  />
  + {{! Left Side (Band, Service Dropdown) }}
  <BsDropdown
  data-test-service-list
  data-analytics-scope='Services dropdown'
  {{/each}}
  </dropdown.menu>
  </BsDropdown>
  - {{/if}}
  </nav.section>
  {{! Right Side (Search, Buttons, Gravatar, Dropdown) }}
  