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

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https://hg.mozilla.org/integration/gaia-central/rev/be77dd251d87
Author: Francisco Jordano <arcturus@ardeenelinfierno.com>
Desc: Merge pull request #16372 from arcturus/bug-969293

[FTE] In FTE, when PIN is inserted, I can't see "Cellular data" screen instead i see "Select a network" screen

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https://hg.mozilla.org/integration/gaia-central/rev/fff74cfe0664
Author: Francisco Jordano <arcturus@ardeenelinfierno.com>
Desc: [FTE] In FTE, when PIN is inserted, I can't see "Cellular data" screen instead i see "Select a network" screen
Bumping manifests a=b2g-bump