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

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https://hg.mozilla.org/integration/gaia-central/rev/a58ab122a656
Author: Julien Wajsberg <felash@gmail.com>
Desc: Merge pull request #22841 from julienw/1053276-fix-activity-handler-tests

Bug 1053276 - [Messages] ActivityHandler tests are failing if the test a...

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https://hg.mozilla.org/integration/gaia-central/rev/6c28c1d1447d
Author: Julien Wajsberg <felash@gmail.com>
Desc: Bug 1053276 - [Messages] ActivityHandler tests are failing if the test agent is hidden r=azasypkin
Bumping manifests a=b2g-bump