Bumping gaia.json for 4 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/b55d2780462e
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Merge pull request #19261 from etiennesegonzac/bug-986062-edge-reflow-take-2

Bug 986062 edge reflow take 2 r=vingtetun,janx

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https://hg.mozilla.org/integration/gaia-central/rev/6f5cf42576b3
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Bug 986062 - Adding an integration test making sure we don't reflow during edge gestures. Take #2.

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https://hg.mozilla.org/integration/gaia-central/rev/6dec66e2f9eb
Author: Arnau <arnau@arnaumarch.com>
Desc: Merge pull request #19322 from pacorampas/replace-images-dialer-1010129

Bug 1010129 - [Dialer] Replace outdated icons and add missing ones. r=rik

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https://hg.mozilla.org/integration/gaia-central/rev/c5bf4db8dc3d
Author: Paco Rampas <pacorampas@gmail.com>
Desc: Bug 1010129 - [Dialer] Replace outdated icons and add missing ones.
Bumping manifests a=b2g-bump