[Task]: Notify Legal when a takedown action has taken place or is held for 2nd level approval

[diox]

Description

When we process a legal takedown action (#16253), members of a group on AMO should be notified by email that either:

• A takedown has put in second level approval queue and execution has paused
• A takedown has been executed (regardless of whether the execution was automatic or manual, i.e. when the add-on was approved in second-level)

Acceptance Criteria

• Notification is sent for takedowns held for 2nd level
• Notification is sent for takedowns action itself

┆Issue is synchronized with this Jira Task

[eviljeff]

Is this a request from someone, or a request from a PRD/doc? (And if the latter, are there any other unsurfaced requirements?)

[diox]

This is something @wagnerand-moz noted was in the PRD as a must-have but had not had an issue filed until now.