Bumping gaia.json for 4 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/f121adce0117
Author: Ryan VanderMeulen <rvandermeulen@mozilla.com>
Desc: Merge pull request #22632 from guilherme-pg/bug1050396-stop-ringing

Bug 1050396 - Properly handle zero duration in ring command.

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https://hg.mozilla.org/integration/gaia-central/rev/53c5441f5edd
Author: Guilherme Goncalves <guilherme.p.gonc@gmail.com>
Desc: Bug 1050396 - Properly handle zero duration in ring command.

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https://hg.mozilla.org/integration/gaia-central/rev/1428ac15e1f5
Author: Ryan VanderMeulen <rvandermeulen@mozilla.com>
Desc: Merge pull request #22577 from tauzen/Bug1049566

Bug 1049566 - [NFC] add missing unit tests for NfcManager, r=gweng

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https://hg.mozilla.org/integration/gaia-central/rev/b6e0e4e465c9
Author: Krzysztof Mioduszewski <kmioduszewski@gmail.com>
Desc: Bug 1049566 - [NFC] add missing unit tests for NfcManager, r=gweng
Bumping manifests a=b2g-bump