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

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https://hg.mozilla.org/integration/gaia-central/rev/939e15ea2ecd
Author: George <georgeiscoming@gmail.com>
Desc: Merge pull request #23073 from cctuan/1046505

Bug 1046505 - [Text Selection] Implement temporary shortcut for utility bubble.

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https://hg.mozilla.org/integration/gaia-central/rev/1a7d61600b3e
Author: cctuan <georgeiscoming@gmail.com>
Desc: Bug 1046505 - [Text Selection] Implement temporary shortcut for utility bubble.
Bumping manifests a=b2g-bump