Global Search New Navigation - state

What does this MR do and why?

Adds state needed left menu for the advanced search page.

MR sequence	status
1. Global Search New Navigation - fundation	in review
2. Global Search New Navigation - part 1	in review
3. Global Search New Navigation - state	in review 👈 this
3. Global Search New Navigation - part 2	in review
4. Global Search New Navigation - part 3	in review

Screenshots or screen recordings

before	after

This is a technical depth MR the screenshots are purely illustrational.

How to set up and validate locally

1. Setup the Advanced Search https://gitlab.com/gitlab-org/gitlab-development-kit/blob/main/doc/howto/elasticsearch.md
2. Enable the Advanced Search http://gdk:3000/admin/application_settings/advanced_search
3. Enable and turn on the new left sidebar
4. Visit the search page: http://gdk:3000/search

Validation:

1. In Chrome inspector vue tab (plugin), app 5 component, in the vuex sub-tab, you can see under section state useNewNavigation this state is true or false depending on new navigation is on or off
2. In Chrome inspector vue tab (plugin), app 5 component, in the vuex sub-tab, you can see under section getters navigationItems

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 #382328 (closed)