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

========

https://hg.mozilla.org/integration/gaia-central/rev/6b84d29fdbb8
Author: Arthur Chen <crh0716@gmail.com>
Desc: Merge pull request #11336 from crh0716/895226

Bug 895226 - Add a check on active call r=etienne, a=leo+

========

https://hg.mozilla.org/integration/gaia-central/rev/7a870cd8850d
Author: crh0716 <crh0716@gmail.com>
Desc: Bug 895226 - Get the previous call from handledCalls directly