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

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https://hg.mozilla.org/integration/gaia-central/rev/f4de4fb20543
Author: Salvador de la Puente González <salva@unoyunodiez.com>
Desc: Merge pull request #14923 from TheoChevalier/Bug952805-usage-wifi-data-string-fix

Bug 952805 - [Usage][l12y] wifi-usage and mobile-usage are reused in dif...
r=me

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https://hg.mozilla.org/integration/gaia-central/rev/5cabe242c227
Author: TheoChevalier <theo.chevalier11@gmail.com>
Desc: Bug 952805 - [Usage][l12y] wifi-usage and mobile-usage are reused in different contexts