[Guided onboarding] "Quit guide" functionality

[yuliacech]

We need to add a link "Opt out of guided setup" to the bottom of the guided setup panel. When the user clicks on the link, we will display a confirmation modal that informs the user that they can abandon the guided setup completely but it's possible to return to the guided setup via links on the home page. If they confirm, the guided setup button is removed from the header, the guided setup state is updated to "guided setup has been quitted when a guide was in progress", the panel disappears and the user stays on the same page whether they are currently.

Screenshots

Optionally, we can open the help menu and highlight the guided onboarding link when the user quits the guide. (related issue #139816)

[elasticmachine]

Pinging @elastic/platform-onboarding (Team:Journey/Onboarding)