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

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https://hg.mozilla.org/integration/gaia-central/rev/343689e6afb7
Author: Cristian Rodriguez <crdlc@tid.es>
Desc: Merge pull request #18016 from crdlc/bug-988174-v4

Bug 988174 - Extract UI to edit bookmarks

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https://hg.mozilla.org/integration/gaia-central/rev/d243d8ef218f
Author: crdlc <crdlc@tid.es>
Desc: Bug 988174 - Extract UI to edit bookmarks
Bumping manifests a=b2g-bump