Bumping gaia.json for 4 gaia-central revision(s)

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https://hg.mozilla.org/integration/gaia-central/rev/3f9b2319c2b3
Author: Arthur Chen <crh0716@gmail.com>
Desc: Merge pull request #10918 from crh0716/892393

Bug 892393 - Add 1.5x resolution assets r=rexboy

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https://hg.mozilla.org/integration/gaia-central/rev/26f60f2a526d
Author: crh0716 <crh0716@gmail.com>
Desc: Bug 892393 - Add 1.5x resolution assets

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https://hg.mozilla.org/integration/gaia-central/rev/5140f1fbba25
Author: Francisco Borja Salguero Castellano <fbsc@tid.es>
Desc: Merge pull request #10726 from julienw/885278-updatetimeheaders-with-fixedheader

885278 updatetimeheaders with fixedheader

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https://hg.mozilla.org/integration/gaia-central/rev/8b741e315032
Author: Julien Wajsberg <felash@gmail.com>
Desc: Bug 885278 - [SMS] `updateTimeHeaders' is not working properly with FixedHeader feature. r=borja

* always call refresh in updateTimeHeaders
* expose updateHeaderContent and use it in updateTimeHeaders so that the fixed
  header is changed in the same time than the other headers