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

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https://hg.mozilla.org/integration/gaia-central/rev/83eca346da6f
Author: Guillaume C. Marty <gmarty@users.noreply.github.com>
Desc: Merge pull request #25500 from gmarty/Bug-1086205-Add-an-abstract-class-for-status-bar-icons-for-marionette-tests

Bug 1086205 - Add an abstract class for status bar icons for marionette ...

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https://hg.mozilla.org/integration/gaia-central/rev/a5c190c6a826
Author: Guillaume Marty <edo999@gmail.com>
Desc: Bug 1086205 - Add an abstract class for status bar icons for marionette tests
Bumping manifests a=b2g-bump