Pipeline Graph: Add Stage Name to Needs/Layers VIew

What does this MR do?

This MR adds the stage name to JobItem and JobItemDropdown components in the layers view of the pipeline graph. It is related to #298973 (closed) and #298930 (closed).

While much of the code is behind multiple feature flags (), it does adjust the JobItem and JobItemDropdown slightly in both views. It has been checked in both cases.f

Screenshots (strongly suggested)

old graph	stage view	layers

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 all relevant changes are behind feature flags.
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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.

Related to #298973 (closed)