Migrates GlDropdown to GlCollapsibleListbox in pipeline new ref dropdown

What does this MR do and why?

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This MR resolves #384288 (closed)

Migrates <GlDropDown> to the new <GlCollapsibleListbox> component. This is part of the dropdown migration OKR.

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Go to Project -> CI/CD -> Pipelines -> Run pipeline

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Related to #384288 (closed)