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

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https://hg.mozilla.org/integration/gaia-2_1/rev/2e7a2f731f3b
Author: Ryan VanderMeulen <ryanvm@gmail.com>
Desc: Merge pull request #24959 from marshall/bug1070858_appUsageOnline_v2.1

Bug 1070858: [AppUsageMetrics] Track online status through navigator.onLine

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https://hg.mozilla.org/integration/gaia-2_1/rev/ffd0cc841ada
Author: Marshall Culpepper <marshall@mozilla.com>
Desc: Bug 1070858: [AppUsageMetrics] Track online status through navigator.onLine r=djf
Bumping manifests a=b2g-bump