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

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https://hg.mozilla.org/integration/gaia-central/rev/aac453d74085
Author: Jose M. Cantera <jmcanterafonseca@gmail.com>
Desc: Merge pull request #17096 from fcampo/export-footer-stuck-977368

Bug 977368 - [Contacts] The export footer message gets stuck after exporting multiple times

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https://hg.mozilla.org/integration/gaia-central/rev/65824ec733a3
Author: Fernando Campo <fernando.campo@o2.com>
Desc: Bug 977368 - [Contacts] The export footer message gets stuck after exporting multiple times
Bumping manifests a=b2g-bump