[OM] Update diagram explaining the backup process for FCV 4.2 (and higher) shows markers for 6 steps, but the description explains only 5 steps

Description

https://docs.opsmanager.mongodb.com/current/core/backup-overview/

Look at the diagram from the first screenshot - there is a marker for a Step 6.

Look at the steps explained in the second screenshot - there are only 5 steps.

Scope of changes

Impact to Other Docs

MVP (Work and Date)

Resources (Scope or Design Docs, Invision, etc.)