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

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https://hg.mozilla.org/integration/gaia-central/rev/7f61d8b139b5
Author: Germán Toro del Valle <gtorodelvalle@gmail.com>
Desc: Merge pull request #18934 from gtorodelvalle/dialer-bug-1003846-call-duration-when-ended

Bug 1003846 - [Dialer][Call Screen] Show the call duration when it ends

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https://hg.mozilla.org/integration/gaia-central/rev/f63706a8cf69
Author: German Toro del Valle <gtorodelvalle@gmail.com>
Desc: Bug 1003846 - [Dialer][Call Screen] Show the call duration when it ends
Bumping manifests a=b2g-bump