Add a "Show Details" context action to ListItem's with non-null Details when a Page's ShowDetails = false

[zadjii-msft]

If the page returns ShowDetails = true, the DevPal automatically expand out
the Details for list items with Details set to a non-null value.
If ShowDetails = false, the DevPal will not expand out the details for list
items by default, but will add a "Show details" action to the item's list of
actions (if it sets Details).

• For example: in the Windows Search box, when you search for an app, you get a
  "details" that is pre-expanded.
• Similarly for file searches - you get a preview of the file, and metadata on
  those details for the file path, last modified time, etc.
• But something like the "GitHub" extension may not want to always fetch issue
  bodies to show their details by default. So it would set ShowDetails = false. If the user activates the automatic "Show details" action, then the
  github action can then fetch the body and show it.