[HelpHub] Overhaul Modified Date block

[andreawetzel]

Issue Description

The Modified Date block is out of date compared to WordPress 7.0 behavior.

Screenshots and text need to be updated.

URL of the Page with the Issue

https://wordpress.org/documentation/article/post-modified-date-block/

[github-actions]

Heads up @WordPress/docs-issues-coordinators, we have a new issue open. Time to use 'em labels.

[andreawetzel]

This page is ready for review: https://wordpress.org/documentation/article/post-modified-date-block/

[github-actions]

Heads up @docs-reviewers - the "[Status] Review" label was applied to this issue.