Bumping gaia.json for 3 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-2_1/rev/1906f0a91690
Author: albertopq <albert.pastor@gmail.com>
Desc: Merge pull request #26687 from albertopq/v2.1-1090859-2

Bug 1090859 - Fixing race condition between applications.ready and SIM dialog

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https://hg.mozilla.org/integration/gaia-2_1/rev/847e056a1ae6
Author: albertopq <albert.pastor@gmail.com>
Desc: Bug 1090859 - Fixing race condition between applications.ready and SIM dialog

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https://hg.mozilla.org/integration/gaia-2_1/rev/7eab072629df
Author: albertopq <albert.pastor@gmail.com>
Desc: Revert "Bug 1090859 - Fixing race condition between applications.ready and SIM dialog"

This reverts commit bf6a6af71c7a3c003382df1130a46763bad63d03.
Bumping manifests a=b2g-bump