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

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https://hg.mozilla.org/integration/gaia-central/rev/a74fb527b6e7
Author: Aleh Zasypkin <aleh.zasypkin@gmail.com>
Desc: Merge pull request #26024 from azasypkin/bug-1096898-usage-in-mulet

Bug 1096898 - [Usage] Make Usage app work in Mulet. r=salva

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https://hg.mozilla.org/integration/gaia-central/rev/9e4af505c9ca
Author: Aleh Zasypkin <azasypkin@mozilla.com>
Desc: Bug 1096898 - [Usage] Make Usage app work in Mulet. r=salva
Bumping manifests a=b2g-bump