Draft: Adds a message on completion notes for Dedicated upgrades

What

We add a new section in the Dedicated toil template with instructions on how the Engineer on-call will notify that the upgrade to a Dedicated tenant instance was successful.

Why

As discussed in last week's team sync meeting. Until we have the automation in place to get updates on non triggered Dedicated upgrade jobs, we will keep validating manually that the Dedicated tenant instance upgrade was successful.