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

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https://hg.mozilla.org/integration/gaia-central/rev/73b225c7c662
Author: Sherman Chen <shamenchens@users.noreply.github.com>
Desc: Merge pull request #23255 from shamenchens/Bug1054943-ActionMenuButton

Bug 1054943 - Update button css for action menu, r=alive

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https://hg.mozilla.org/integration/gaia-central/rev/9a5459a6311b
Author: Sherman Chen <shamen.chens@gmail.com>
Desc: Bug 1054943 - Update button css for action menu
Bumping manifests a=b2g-bump