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

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https://hg.mozilla.org/integration/gaia-central/rev/46116d02329e
Author: Wilson Page <wilsonpage@me.com>
Desc: Merge pull request #24762 from wilsonpage/1076907

Bug 1076907 - Update gaia-icons, gaia-header and gaia-theme to latest

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https://hg.mozilla.org/integration/gaia-central/rev/5456b12b6ad7
Author: Wilson Page <wilsonpage@me.com>
Desc: Bug 1076907 - Update gaia-icons, gaia-header and gaia-theme to latest
Bumping manifests a=b2g-bump