Pipeline Graph: Update graph state selection

What does this MR do?

This MR updates the way the graph is displayed and adds the links toggle. All work is behind the pipelineGraphLayersView feature flag. The dropdown is replaced with a a segmented selector and, when the layers view is selected, a toggle to hide and show links appears. Both controls also show loading states.

Screenshots (strongly suggested)

Does this MR meet the acceptance criteria?

Conformity

• 📋 Does this MR need a changelog?
  • I have included a changelog entry.
  • I have not included a changelog entry because ff.
• Code review guidelines
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Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers

Related to #298973 (closed)

app/assets/javascripts/pipelines/components/graph/graph_component_wrapper.vue

@@ -199,12 +199,12 @@ export default {
       {{ alert.text }}
     </gl-alert>
     <local-storage-sync
+      v-if="showGraphViewSelector"
       :storage-key="$options.viewTypeKey"
       :value="currentViewType"
       @input="updateViewType"
     >
       <graph-view-selector
-        v-if="showGraphViewSelector"
         :type="currentViewType"
         :show-links="showLinks"
         @updateViewType="updateViewType"