Editor welcome: Update display logic for an existing user

[razvanpapadopol]

Note: before starting the implementation for this task, check out #57660

What

Stop displaying the Editor Welcome Tour for 30 days after the user dismissed it.

Current status: the Tour is forced to be displayed for any site that is maximum 30 minutes old, regardless if and when the user dismissed it previously.
Also, a dismissal status is stored in local storage to be used in this interval (30 minutes) and that may cause issues with the welcome tour reappearing (see #57660).

Why

• Editor Welcome tour should be there to guide the users when they need it and it shouldn't be annoying.
• As part of the Help Center initiative, the tour (together with other tours) will be more accessible to restart.

A/C

• Update API to store the timestamp of the last tour completion (or dismissal) event in the user option where the dismissal flag is already stored.
• Update client-side logic:
  • stop forcing the Tour in the first 30 minutes for a new site
  • save the timestamp of the dismissal
  • show the tour based only on the user option when the tour hasn't been completed (or dismissed) in the past 30 days.

---

Notes:

• Keep in mind the users will have the current override value in the local storage.
• See how something like this is done in Calypso, for the App banner: https://github.com/Automattic/wp-calypso/blob/trunk/client/blocks/app-banner/index.jsx#L263
• Example of an API change for a site: D60468-code