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

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https://hg.mozilla.org/integration/gaia-central/rev/ad16ef5cf27b
Author: Jose M. Cantera <jmcanterafonseca@gmail.com>
Desc: Merge pull request #22144 from ADLR-es/fix_bug_1027313

Bug 1027313 - [B2G][Contacts][Facebook]Removing all Facebook Data from d...

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https://hg.mozilla.org/integration/gaia-central/rev/a855080343f2
Author: Adrián de la Rosa <hola@adlr.es>
Desc: Bug 1027313 - [B2G][Contacts][Facebook]Removing all Facebook Data from device without other Contacts saved displays Delete Contacts button to select contacts that do not exist
Bumping manifests a=b2g-bump