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

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https://hg.mozilla.org/integration/gaia-central/rev/b6833b91863b
Author: steveck-chung <schung@mozilla.com>
Desc: Merge pull request #19702 from steveck-chung/message-vr-delivery-read-icon

Bug 1010093 - [Message] Visual refresh for delivery/read report icon in thread view. r=azasypkin

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https://hg.mozilla.org/integration/gaia-central/rev/30c5e2704fba
Author: Steve Chung <schung@mozilla.com>
Desc: Bug 1010093 - [Message] Visual refresh for delivery/read report icon in thread view. r=azasypkin
Bumping manifests a=b2g-bump