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

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https://hg.mozilla.org/integration/gaia-central/rev/f47616f5a144
Author: Arnau <arnau@arnaumarch.com>
Desc: Merge pull request #21272 from pacorampas/1029955

Bug 1029954 - [Dialer][Call Screen][Conference] Icon size is larger than others and overlapped with 'Conference' when call hanging up r=rik

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https://hg.mozilla.org/integration/gaia-central/rev/757dd70d7a07
Author: Paco Rampas <pacorampas@gmail.com>
Desc: Bug 1029955 - [Dialer][Call Screen][Conference] Icon size is larger than others when 3rd call is answered
Bumping manifests a=b2g-bump