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

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https://hg.mozilla.org/integration/gaia-central/rev/2e54909d4fc8
Author: Florin Strugariu <bebef_1987@yahoo.com>
Desc: Merge pull request #19928 from AndreiH/bug_1018207

Bug 1018207 - Wait for loading screen icon in camera tests

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https://hg.mozilla.org/integration/gaia-central/rev/350973c0b8fe
Author: Andrei Hutusoru <andreihutusoru@P5069.(none)>
Desc: Bug 1018207 - [v1.4] Test camera flash modes is failing on v1.4
Bumping manifests a=b2g-bump