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

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https://hg.mozilla.org/integration/gaia-central/rev/4c3ffab8bf39
Author: Min-Zhong "John" Lu <jlu@mozilla.com>
Desc: Merge pull request #25798 from mnjul/bug_1093477_remove_input_test_mocks

Bug 1093477 - Remove usage of MockInputWindowManager in KeyboardManager unit tests. r=timdream

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https://hg.mozilla.org/integration/gaia-central/rev/3d84aaffd426
Author: John Lu [:mnjul] <jlu@mozilla.com>
Desc: Bug 1093477 - Remove usage of mocks in KeyboardManager/InputWindowManager unit tests

Use stubbed InputWindowManager.prototype and InputWindow.prototype instead.
Bumping manifests a=b2g-bump