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

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https://hg.mozilla.org/integration/gaia-central/rev/7702b96fd4bc
Author: Anthony Ricaud <anthony@ricaud.me>
Desc: Merge pull request #21367 from Rik/mmi-test-broken-1032784

Bug 1032784 - Some MMI unit tests are broken r=etienne

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https://hg.mozilla.org/integration/gaia-central/rev/7d9935889f1b
Author: Anthony Ricaud <anthony@ricaud.me>
Desc: Bug 1032784 - Some MMI unit tests are broken
Bumping manifests a=b2g-bump