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

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https://hg.mozilla.org/integration/gaia-central/rev/559cd63d39f8
Author: Fabrice Desré <fabrice@desre.org>
Desc: Merge pull request #23178 from fabricedesre/bug1054355

Bug 1054355 - Respect isApp property of mozbrowseropenwindow event r=ali...

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https://hg.mozilla.org/integration/gaia-central/rev/7bf859339e92
Author: Fabrice Desré <fabrice@desre.org>
Desc: Bug 1054355 - Respect isApp property of mozbrowseropenwindow event r=alive
Bumping manifests a=b2g-bump