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

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https://hg.mozilla.org/integration/gaia-central/rev/d7e18028030c
Author: Fernando Campo <fernando.campo@telefonica.com>
Desc: Merge pull request #19444 from fcampo/split-basket-990058

Bug 990058 - [FTU] Re-implement Basket newsletter for splitted FTU (r=arcturus, etienne)

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https://hg.mozilla.org/integration/gaia-central/rev/c254a88ac066
Author: Fernando Campo <fernando.campo@telefonica.com>
Desc: Bug 990058 - [FTU] Re-implement Basket newsletter for splitted FTU
- Basket functionality moved to shared, use Promises
- Use DataStore instead of AsyncStore
- Launched from System instead of Dialer
Bumping manifests a=b2g-bump