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

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https://hg.mozilla.org/integration/gaia-central/rev/4f3818d9c557
Author: Florin Strugariu <florin.strugariu@softvision.ro>
Desc: Merge pull request #26229 from davehunt/bug1074117-email

Bug 1074117 - Use expected conditions and optimise element lookups in email app object

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https://hg.mozilla.org/integration/gaia-central/rev/5b190267fce7
Author: Dave Hunt <dave.hunt@gmail.com>
Desc: Bug 1074117 - Use expected conditions where appropriate and optimise element lookups in email app object. r=fstrugariu
Bumping manifests a=b2g-bump