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

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https://hg.mozilla.org/integration/gaia-central/rev/b1741ea6d91c
Author: Evyatar Amitay <evyatron@gmail.com>
Desc: Merge pull request #12553 from EverythingMe/collection-rename

[Bug 911550] Enable collection renaming [r=crdlc]

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https://hg.mozilla.org/integration/gaia-central/rev/ddbe7195057c
Author: Evyatar Amitay <evyatron@gmail.com>
Desc: [Bug 911550] Enable collection renaming [r=crdlc]