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

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https://hg.mozilla.org/integration/gaia-central/rev/a9b27d338720
Author: Zibi Braniecki <zbigniew.braniecki@gmail.com>
Desc: Merge pull request #20586 from zbraniecki/998094-global-pretranslate-flag

998094 global pretranslate flag. r=stas

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https://hg.mozilla.org/integration/gaia-central/rev/6ebbde518c20
Author: Zbigniew Braniecki <gandalf@mozilla.com>
Desc: 998094 - introduce GAIA_PRETRANSLATE global flag
Bumping manifests a=b2g-bump