Add Snowplow tracking to VSD metric drill-down links

What does this MR do and why?

Adds Snowplow tracking events to the Value Stream Dashboard metric drill-down links.

Screenshots or screen recordings

No visual changes.

Sample Snowplow tracking event

How to set up and validate locally

Setup Snowplow locally

1. Enable Snowplow in your GDK.
2. Configure your local setup to test frontend Snowplow events

Validation steps

1. Please make sure that you have a GitLab Ultimate license
2. Create a group
3. Seed cycle analytics data
4. Seed dora metrics data
5. Visit the Value streams dashboard, click on every metric drill-down and, using one of the Snowplow Chrome extensions, validate that their respective tracking events are present

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.

Related to #409474 (closed)