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

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https://hg.mozilla.org/integration/gaia-central/rev/6191c1089939
Author: Cristian Rodriguez <crdlc@tid.es>
Desc: Merge pull request #19931 from crdlc/bug-1019534

Bug 1019534 - [Collection App] Migrate data to vertical homescreen format

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https://hg.mozilla.org/integration/gaia-central/rev/7a62a76f4bf7
Author: crdlc <crdlc@tid.es>
Desc: Bug 1019534 - [Collection App] Rename providerId to categoryId
Bumping manifests a=b2g-bump