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

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https://hg.mozilla.org/integration/gaia-central/rev/23a559f77352
Author: Timothy Guan-tin Chien <timdream@gmail.com>
Desc: Merge pull request #25475 from timdream/keyboard-alt-logic

Bug 1088474 - Fix a minor TypeError in AlternativesCharMenuManager, r=mnjul

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https://hg.mozilla.org/integration/gaia-central/rev/8570083ec32a
Author: Timothy Guan-tin Chien <timdream@gmail.com>
Desc: Bug 1088474 - Fix a minor TypeError in AlternativesCharMenuManager
Bumping manifests a=b2g-bump