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

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https://hg.mozilla.org/integration/gaia-central/rev/aa809deda51f
Author: gasolin <gasolin@gmail.com>
Desc: Merge pull request #17848 from gasolin/issue-984802

Bug 984802 - [MADAI][System] @2.25x assets update for System, r=alive

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https://hg.mozilla.org/integration/gaia-central/rev/d1fd94c03cd9
Author: gasolin <gasolin@gmail.com>
Desc: Bug 984802 - [MADAI][System] @2.25x assets update for System
Bumping manifests a=b2g-bump