Update ML Engineering Manager role based on feedback

Why is this change being made?

Addressing feedback from @schoi4 : !211 (comment 1466057854)

@glucchesi @wayne Since the expectations of the 'Engineering Manager Machine Learning' is to be a people manager, could we update the title to be 'Manager, Machine Learning Engineering'? Also, the responsibilities seem a little light for the Manager role - perhaps some things to add if true, could be that the more complex issues/tasks would be escalated to this level, or is it an extension of the Senior level responsibilities with added complexity, etc. Can mimic staff level but with people responsibilities, etc.? What other responsibilities/scope/knowledge would separate this Manager level from the other levels/roles?

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