Add additional analytics dashboard user events

What does this MR do and why?

This MR adds two more user events to analytics dashboards:

• user_viewed_builtin_dashboard when a user visits any builtin / GitLab provided dashboard
• user_viewed_dashboard when a user visits any analytics dashboard

This adds to the existing user_viewed_custom_dashboard event when a user views custom (non-builtin) dashboards.

Related issue Update tracking for cases where users view an a... (#413646 - closed).

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

No visual changes.

How to set up and validate locally

To set up Product Analytics feature:

1. Follow these instructions to setup Product Analytics in GDK.
2. Onboard Product Analytics by setting up the feature at Project > Analytics > Analytics dashboards.

To verify the events:

1. Navigate to Project > Analytics > Analytics dashboards.
2. View any dashboard marked with Created by GitLab to trigger the user_viewed_builtin_dashboard event.
3. Click on New dashboard to create a new dashboard.
4. Open your newly created custom dashboard to trigger the user_viewed_custom_dashboard event.
5. Viewing any analytics dashboard should also trigger the user_viewed_dashboard event.