Bust cache when changing spaces

[jeremyf]

What type of PR is this? (check all applicable)

• Feature

Description

In the app/views/layouts/application.html.erb we use
ApplicationHelper#release_adjusted_cache_key to define a cache
key. That cache key includes the
Settings::General.admin_action_taken_at time field.

The ApplicationController#bust_content_change_caches method is
responsible for updating the Settings::General.admin_action_taken_at column.

Related Tickets & Documents

This relates to #16606 and may be necessary for the
following:

• Ensure that the Moderator Tools for a post are only visible to moderators when we have not enabled limit posts to admin #16783
• On individual tags pages (e.g. /t/:tag_name) apply policy for creating an article #16836
• Conditionally render "My Posts Only" section of search results #16837
• Conditionally render "Create Post" in user drop down menu #16965
• What to show for the organization's dashboard when current user is org admin but not site admin #17008

QA Instructions, Screenshots, Recordings

For this to be meaningfully tested, you'll need to spin up community.benhalpernc.com.

UI accessibility concerns?

None.

Added/updated tests?

• No, and this is why: I'm waiting on the finalization of the UI behavior
  for the /admin/content_manager/spaces before writing a more robust
  spec.

[Forem core team only] How will this change be communicated?

• I will share this change internally with the appropriate teams