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

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https://hg.mozilla.org/integration/gaia-central/rev/d8f00462c758
Author: Anthony Ricaud <anthony@ricaud.me>
Desc: Merge pull request #14273 from Rik/contact-in-dialer-fake-943779

Bug 943779 - Need to update the images displayed while the contact tab i... r=etienne

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https://hg.mozilla.org/integration/gaia-central/rev/cd721706646f
Author: Anthony Ricaud <anthony@ricaud.me>
Desc: Bug 943779 - Need to update the images displayed while the contact tab is loading with the new visuals

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https://hg.mozilla.org/integration/gaia-central/rev/bf92c353ee7e
Author: gitmai <mri@tid.es>
Desc: Merge pull request #14308 from gitmai/bug-944718-Broken-usage-widget

Bug 944718 - [Cost Control] Broken access to usage widget from utility t...
r=salva

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https://hg.mozilla.org/integration/gaia-central/rev/e482b7bf2da3
Author: mai <mri@tid.es>
Desc: Bug 944718 - [Cost Control] Broken access to usage widget from utility tray