Replace transfer project confirmation modal with GlModal

What does this MR do and why?

Related to #342116 (closed) #345131 (closed) #250697 (closed)

• Replaces the haml danger confirm modal used for project transfer with a GlModal
• Replaces haml dropdown selector with a GlDropdown

Screenshots or screen recordings

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How to set up and validate locally

1. Navigate to an existing project's settings page, for example http://<gdk>/flightjs/flight/edit
2. Scroll to the bottom and expand the advanced section
3. Under Transfer project select a new namespace from the dropdown
4. Click the transfer project button then confirm the project name

MR acceptance checklist

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