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

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https://hg.mozilla.org/integration/gaia-central/rev/f48e957acb14
Author: Yuren Ju <yurenju@gmail.com>
Desc: Merge pull request #17276 from yurenju/keyboard/935859

Bug 935859 - [Keyboard] Remove the "sendString" method from pinyin IME

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https://hg.mozilla.org/integration/gaia-central/rev/13eadf7fef57
Author: Sherman Chen <shamen.chens@gmail.com>
Desc: Bug 935859 - [Keyboard] Remove the "sendString" method from pinyin IME
Bumping manifests a=b2g-bump