Track pipeline simulation in the pipeline editor

What does this MR do and why?

For #369589 (closed)

This adds snowplow tracking for when the user simulates their pipeline in the pipeline editor, and when they simulate it again after changing the content of their YAML config file.

Screenshots or screen recordings

Screen_Recording_2022-08-11_at_16.04.56

How to set up and validate locally

Set up Snowplow Testing

1. Make sure Do Not Track browser setting is disabled. Disable other anti-tracking plugins (e.g. uBlock, Ghostery, etc).
2. Enable Snowplow tracking on admin (Docs). We can use the following values in the form.

Hostname: your-snowplow-collector.net
App ID: gitlab
Cookie domain: .your-gitlab-instance.com

1. Install the Snowplow Debugger or Snowplow Inspector plugin. Either works. Docs
2. Recommended/Optional: Set up Snowplow Micro. This will streamline the events being recorded. If snowplow micro is not set up, multiple events will be recorded as the app tries to resend them.
   1. Make sure docker is running and gdk is configured to use it. To know if micro was set up correctly, visit http://localhost:9091/micro/all.

Verify Changes

1. Open the debugger menu on the browser then go to the pipeline editor (CI/CD > Editor).
2. If events are not being recorded, you may need to refresh the page with the menu open.
3. Go to the Validate tab and click on the Validate pipeline button.
4. To simulate your pipeline again, edit the YAML configuration in the Edit tab then click on the Validate pipeline button again.
5. Verify that the events are tracked properly.

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.