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

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https://hg.mozilla.org/integration/gaia-1_3/rev/ad2e4a739345
Author: Michael Henretty <michael.henretty@gmail.com>
Desc: Revert "Merge pull request #16910 from gtorodelvalle/contacts-bug-972600-add-contact-after-merging"

This reverts commit bfc6b263d296bd32422164d8f42097a4dc52c39c.
Bumping manifests a=b2g-bump