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

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https://hg.mozilla.org/integration/gaia-central/rev/e1a248ef8887
Author: David Flanagan <dflanagan@mozilla.com>
Desc: Merge pull request #13926 from davidflanagan/demokbd3

demo-keyboard app: bug fixes and layout variant handling

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https://hg.mozilla.org/integration/gaia-central/rev/fa0b272c824e
Author: David Flanagan <dflanagan@mozilla.com>
Desc: bug fixes and wip on variant handling

bug fixes