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

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https://hg.mozilla.org/integration/gaia-central/rev/704563ba3b61
Author: Zac <zcampbell@mozilla.com>
Desc: Merge pull request #14116 from viorelaioia/bug_943579

Bug 943579 - override timeout in wait_for_notification_toaster_not_displ...

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https://hg.mozilla.org/integration/gaia-central/rev/7c83c5fc6d50
Author: Viorela Ioia <viorelaioia@gmail.com>
Desc: Bug 943579 - override timeout in wait_for_notification_toaster_not_displayed()