Bumping gaia.json for 1 gaia-central revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/946bdbc626ce
Author: Zac Campbell <zcampbell@mozilla.com>
Desc: Revert "Bug 939062 - Improve wait in test_add_contact_to_favorites.py"

This reverts commit b5639f1512df1905cdcfa806c1367f2650248315.