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

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https://hg.mozilla.org/integration/gaia-central/rev/18ebdfd30a2d
Author: Johan Lorenzo <jlorenzo@mozilla.com>
Desc: Merge pull request #26850 from bebef1987/import_connection

Bug 1109586 - Write test to check the Contacts App checks and notifies t...

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https://hg.mozilla.org/integration/gaia-central/rev/6b8229568745
Author: bebef1987 <florin.strugariu@softvision.ro>
Desc: Bug 1109586 - Write test to check the Contacts App checks and notifies the user when no network is available during a import contacts app
Bumping manifests a=b2g-bump