Bumping gaia.json for 2 gaia-central revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/0c8219fa9492
Author: Ryan VanderMeulen <rvandermeulen@mozilla.com>
Desc: Merge pull request #13364 from gnarf/933167

Bug 933167 - [Keyboard][V1.2] The settings value of third party keyboard will be kept if uninstalling the in used keyboard

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https://hg.mozilla.org/integration/gaia-central/rev/6add91433158
Author: Corey Frang <gnarf37@gmail.com>
Desc: Bug 933167 - [Settings][V1.2] The settings for third party keyboards will still display after uninstalling the keyboard - r=arthur.chen

- Updated _initInstalledLayoutListView to use `ListView` of keyboards, within a `ListView` of layouts.
- Abstracted observing method to a helper for ListView provide easier detachment points