Add keys to the pusher page GridRows
Add keys to the pusher page GridRows

Summary:
Avoids a warning, and probably makes some of the updating possible with finer granularity, though
I haven't verified that.
Also, moved to es6-style methods because they look nicer to me.

Test Plan: Manual

Reviewers: angie

Reviewed By: angie

Subscribers: changesbot

Tags: #changes_ui

Differential Revision: https://tails.corp.dropbox.com/D200040

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