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

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https://hg.mozilla.org/integration/gaia-central/rev/ff38ee67433b
Author: Rudy Lu <me@rudy.lu>
Desc: Merge pull request #26054 from RudyLu/valueSelector/Bug1094550-forTrusted_UI

Bug 1094550 - Unable to create a new account because Year of Birth dropdown
r=alivedise.

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https://hg.mozilla.org/integration/gaia-central/rev/91224f32df3e
Author: Rudy Lu <me@rudy.lu>
Desc: Bug 1094550 - Unable to create a new account because Year of Birth
dropdown doesn't work.
 - Create a value selector overlay to listen to the event for showing value selector for trusted
   UI.
 - Let trusted UI module init its own value selector controller.
Bumping manifests a=b2g-bump