eslint: turn of react/forbid-prop-types
eslint: turn of react/forbid-prop-types

We agree that people _should_ not use PropTypes.object normally, but
there _are_ times where doing that makes more sense then trying to come
up with a PropTypes.shape to use instead. So this is something we think
should be enforced in code-review rather than -2ing commits because
of it. We’d rather get rid of the rule than see a bunch of 
`eslint-disable-next-line react/forbid-prop-types` scattered around
trying to ignore it where people knew what they were doing.

Test plan:
* you shouldn’t see any more warnings about 
  `PropTypes.object is forbidden` when you eslint

Change-Id: Icc9071604a162260aa9bce3a916f046f2553b66a
Reviewed-on: https://gerrit.instructure.com/209451
Tested-by: Jenkins
Reviewed-by: Ed Schiebel <0ca8a83847a5889cf05cb219c0ab09f6b646243b@instructure.com>
QA-Review: Ryan Shaw <ea3cd978650417470535f3a4725b6b5042a6ab59@instructure.com>
Product-Review: Ryan Shaw <ea3cd978650417470535f3a4725b6b5042a6ab59@instructure.com>

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