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

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https://hg.mozilla.org/integration/gaia-central/rev/5162ae280c33
Author: Ben Francis <ben@tola.me.uk>
Desc: Merge pull request #15782 from benfrancis/963173

Bug 963173 - Ensure address bar is always displayed when a different tab is selected r=daleharvey

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https://hg.mozilla.org/integration/gaia-central/rev/adefe8f682ed
Author: Ben Francis <ben@tola.me.uk>
Desc: Bug 963173 - Ensure address bar is always displayed when a different tab is selected
Bumping manifests a=b2g-bump