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

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https://hg.mozilla.org/integration/gaia-central/rev/16ec3b9b6e68
Author: Wilson Page <wilsonpage@me.com>
Desc: Merge pull request #22416 from wilsonpage/1024993

Update gaia-icons to v0.2.5

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https://hg.mozilla.org/integration/gaia-central/rev/8664a4dafa25
Author: Wilson Page <wilsonpage@me.com>
Desc: Update gaia-icons to v0.2.5
Bumping manifests a=b2g-bump