Use dot notation in some places

Summary: Use x.y in favor of x['y'] in some JavaScript callsites. Note that there are a bunch of places where the latter is explicitly used to trick PhabricatorJavelinLinter.

Test Plan: arc lint

Reviewers: epriestley, Blessed Reviewers

Reviewed By: epriestley, Blessed Reviewers

Subscribers: Korvin, epriestley

Differential Revision: https://secure.phabricator.com/D11442