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

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https://hg.mozilla.org/integration/gaia-central/rev/c5637310d63e
Author: Michał Budzyński <michal@virtualdesign.pl>
Desc: Merge pull request #18954 from michalbe/Bug984584

Bug 984584 - Contacts phone numbers highlighted red when missed

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https://hg.mozilla.org/integration/gaia-central/rev/a0908ee5ac2a
Author: Michal Budzynski <michal@virtualdesign.pl>
Desc: [Bug 984584] - Contacts phone numbers highlighted red when missed
Bumping manifests a=b2g-bump