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

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https://hg.mozilla.org/integration/gaia-central/rev/b5bdd63fc3cd
Author: AndreiH <andrei.hutusoru@softvision.ro>
Desc: Merge pull request #17905 from bebef1987/xfail_cost

Bug 991076 - Xfail test_cost_control_data_alert_mobile failing because B...

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https://hg.mozilla.org/integration/gaia-central/rev/9d6e732bcbc2
Author: Bebe <bebe@mozilla.ro>
Desc: Bug 991076 - Xfail test_cost_control_data_alert_mobile failing because Bug 991067
Bumping manifests a=b2g-bump