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

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https://hg.mozilla.org/integration/gaia-central/rev/8aef23d0842b
Author: Yuren Ju <yurenju@gmail.com>
Desc: Merge pull request #15130 from RickyChien/issue-957932

Bug 957932 - Add coverage execute button for test-agent web interface r=@yurenju

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https://hg.mozilla.org/integration/gaia-central/rev/1dcfdca06ba8
Author: Ricky Chien <ricky060709@gmail.com>
Desc: Bug 957932 - Add coverage checkbox for test-agent web interface
Bumping manifests a=b2g-bump