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

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https://hg.mozilla.org/integration/gaia-central/rev/8f402e9a5c9a
Author: Rex KM Lee <rexboy@mozilla.com>
Desc: Merge pull request #10934 from rexboy7/fix-bug892373-master

Bug 892373 - @1.5x asset revise for Dialer app

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https://hg.mozilla.org/integration/gaia-central/rev/80be3e3a4c6f
Author: Rex Lee <rexboy@mozilla.com>
Desc: Bug 892373 - @1.5x asset revise for Dialer app