re-enable azd tool for update messages

For release 1.28.1 we removed azd tool automatic message offerings and the update message:
https://github.com/Azure/azure-dev/pull/9261

This issue is to re-enable the part about updates, analyzing how to make it simple and w/o annoying folks too often

Start by reviewing PR #9261 to understand why azd automatic messages were removed and which update-message behavior remains. Define a simple update-notification approach that avoids showing messages too often, then verify that update messages are re-enabled without restoring the removed automatic offerings.

Written by the indexing model from the issue text.