Add Snowplow tracking to the help menu

Adds Snowplow tracking attributes to the new sidebar help menu

Related to #402714 (closed)

Tracking events

➕ - new event that is not tracked in the old help menu

Open/close dropdown

	Action	Label	Property
Open dropdown	click_toggle	show_help_dropdown	nav_help_menu
Close dropown	click_toggle	hide_help_dropdown	nav_help_menu

Menu items

User menu item	Action	Label	Property
Help	click_link	help	nav_help_menu
Support	click_link	support	nav_help_menu
GitLab documentation ➕	click_link	gitlab_documentation	nav_help_menu
Compare GitLab plans ➕	click_link	compare_gitlab_plans	nav_help_menu
Community forum	click_link	community_forum	nav_help_menu
Contribute to GitLab	click_link	contribute_to_gitlab	nav_help_menu
Provide feedback	click_link	submit_feedback	nav_help_menu
Keyboard shortcuts	click_button	keyboard_shortcuts_help	nav_help_menu
What's new ➕	click_button	whats_new	nav_help_menu

Screenshots or screen recordings

How to set up and validate locally

1. Enable the super_sidebar_nav feature flag.
2. Log into the GDK and enable the New Navigation for the current user via the User Menu
3. Enable snowplow-micro in your local GDK
4. Install the Snowplow extension in Google Chrome (optional)
5. Click on any item in the help menu and make sure that the event is tracked (either check that request to tp2 endpoint is sent or it is slightly more obvious with Snowplow Chrome Extension)