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

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https://hg.mozilla.org/integration/gaia-central/rev/b0250afb7773
Author: Ryan VanderMeulen <ryanvm@gmail.com>
Desc: Merge pull request #25888 from sv99/1094850

Bug 1094850 - [test-agent] add chai-as-promiced and remove old chai support

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https://hg.mozilla.org/integration/gaia-central/rev/e96db9f105eb
Author: sv99 <sv99@inbox.ru>
Desc: Bug 1094850 - [test-agent] add chai-as-promiced and remove old chai support
Bumping manifests a=b2g-bump