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

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https://hg.mozilla.org/integration/gaia-central/rev/e216b599282a
Author: Michael Henretty <michael.henretty@gmail.com>
Desc: Merge pull request #23779 from mikehenrty/bug-1063087-memoize-homescreen-url

Bug 1063087 - Memoize homescreen url

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https://hg.mozilla.org/integration/gaia-central/rev/16ee9c895ba6
Author: Michael Henretty <michael.henretty@gmail.com>
Desc: Bug 1063087 - Memoize homescreen url r=kgrandon
Bumping manifests a=b2g-bump