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

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https://hg.mozilla.org/integration/gaia-central/rev/abfe3afaff64
Author: Ben Francis <ben@tola.me.uk>
Desc: Merge pull request #14226 from flodolo/addbookmark

Bug 944784 - [l12y][browser] Bookmarks: "Edit Bookmark", use separate strings for button and dialog header

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https://hg.mozilla.org/integration/gaia-central/rev/8246e1f1cb65
Author: Francesco Lodolo (:flod) <flod@lodolo.net>
Desc: Bug 944784 - [browser] Bookmarks: "Edit Bookmark", use separate strings for button and dialog header

Localizers could use a shorter string in the header