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

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https://hg.mozilla.org/integration/gaia-central/rev/5fa77f5e0bff
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Merge pull request #21926 from etiennesegonzac/bug-1039445

Bug 1039445 - Preventing a race where the LayoutManager compute a 0 height. r=alive

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https://hg.mozilla.org/integration/gaia-central/rev/03b32994fe2b
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Bug 1039445 - Preventing a race where the LayoutManager compute an available height of 0.
Bumping manifests a=b2g-bump