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

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https://hg.mozilla.org/integration/gaia-central/rev/8e9e9b06d936
Author: James Burke <jrburke@gmail.com>
Desc: Merge pull request #23246 from karanluthra/1057798-clean-up-mozl10n-api-in-email

BUG 1057798 Clean up mozL10n.{localize(), get()}  use in Email app r=jrburke

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https://hg.mozilla.org/integration/gaia-central/rev/784c003cd5f8
Author: Karan Luthra <karanluthra06@gmail.com>
Desc: BUG 1057798 Clean up mozL10n localize() and get() use in Email app
Bumping manifests a=b2g-bump