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

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https://hg.mozilla.org/integration/gaia-central/rev/dd9804a19173
Author: RickyChien <ricky060709@gmail.com>
Desc: Merge pull request #24421 from RickyChien/bug-1041463

Bug 1041463 - Include a shared CSS file with @import rule r=@cctuan

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https://hg.mozilla.org/integration/gaia-central/rev/e51d4ddcfd35
Author: Ricky Chien <ricky060709@gmail.com>
Desc: Bug 1041463 - Include a shared CSS file with @import rule
Bumping manifests a=b2g-bump