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

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https://hg.mozilla.org/integration/gaia-central/rev/720e0143b553
Author: James Lal <james@lightsofapollo.com>
Desc: Merge pull request #22134 from lightsofapollo/revite-master

Revite master

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https://hg.mozilla.org/integration/gaia-central/rev/eb855c1f023f
Author: William Chen <wchen@mozilla.com>
Desc: Bug 1038439 - Remove web components preference from Gaia. r=vingtetun
Bumping manifests a=b2g-bump