Add pipeline editor walkthrough feature permanently

What does this MR do and why?

This MR implements #352341 (closed).

Since the pipeline editor walkthrough experiment was deemed a success, this MR cleans up the experiment code and updates the feature implementation to make the experiment candidate path the default behavior in the application.

Screenshots or screen recordings

• The drawer in the right is closed by default (previously, opened by default)
• The walkthrough popup shows by default

Screen_Recording_2022-03-11_at_5.47.36_PM

How to set up and validate locally

1. Go to a project without pipelines
2. Go to the Pipeline Editor page
3. Verify that the drawer on the right is closed by default
4. Verify that the walkthrough popup is shown

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.