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

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https://hg.mozilla.org/integration/gaia-central/rev/1719728ee297
Author: steveck-chung <schung@mozilla.com>
Desc: Merge pull request #20396 from steveck-chung/bug-994553

Bug 994553 - [Sora][Message][Contacts]Contacts's head portrait do not display in Message. r=julienw

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https://hg.mozilla.org/integration/gaia-central/rev/344b84c20310
Author: Steve Chung <schung@mozilla.com>
Desc: Bug 994553 - [Sora][Message][Contacts]Contacts's head portrait do not display in Message
Bumping manifests a=b2g-bump