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

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https://hg.mozilla.org/integration/gaia-central/rev/6fdc32e512ef
Author: Germán Toro del Valle <gtorodelvalle@gmail.com>
Desc: Merge pull request #11778 from gtorodelvalle/dialer-bug-867087-shadows-in-call-screens-revolutions

Bug 867087 - [UX] Inconsistent and unreadable callscreen with majorly white contacts pictures (r=etiennesegonzac)

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https://hg.mozilla.org/integration/gaia-central/rev/633dd1faba9b
Author: Germán Toro del Valle <gtorodelvalle@gmail.com>
Desc: Bug 867087 - [UX] Inconsistent and unreadable callscreen with majorly white contacts pictures.