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

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https://hg.mozilla.org/integration/gaia-central/rev/9df8dbc56693
Author: Alive.Kuo <alegnadise@gmail.com>
Desc: Merge pull request #13232 from waalt/926105

Bug 926105 - When there are no apps to show in the app switcher, show a text saying "No recent apps", r=alive

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https://hg.mozilla.org/integration/gaia-central/rev/c66f3497ed85
Author: Adán Sánchez de Pedro Crespo <adansdpc@waalt.com>
Desc: Bug 926105