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

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https://hg.mozilla.org/integration/gaia-central/rev/8d5be9746a87
Author: steveck-chung <schung@mozilla.com>
Desc: Merge pull request #18072 from steveck-chung/bug-983315

Bug 983315 - [Messages][DSDS] Provide a feedback while we're switching the data APN to send a MMS. r=julienw

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https://hg.mozilla.org/integration/gaia-central/rev/282cd3af312b
Author: Steve Chung <schung@mozilla.com>
Desc: Bug 983315 - [Messages][DSDS] Provide a feedback while we're switching the data APN to send a MMS
Bumping manifests a=b2g-bump