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

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https://hg.mozilla.org/integration/gaia-central/rev/bb305d6ed2e7
Author: Cristian Rodriguez <crdlc@tid.es>
Desc: Merge pull request #20600 from crdlc/bug-1026268

Bug 1026268 - [Vertical Homescreen] Cannot exit edit mode by tapping an empty space

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https://hg.mozilla.org/integration/gaia-central/rev/42da99ac80e2
Author: crdlc <crdlc@tid.es>
Desc: Bug 1026268 - [Vertical Homescreen] Cannot exit edit mode by tapping an empty space
Bumping manifests a=b2g-bump