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

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https://hg.mozilla.org/integration/gaia-central/rev/1a1b8e04ea09
Author: Ian Liu <iliu@mozilla.com>
Desc: Merge pull request #14887 from ian-liu/bluetooth/bug951566_fix_unknown_filename_while_sharing_blobs_without_name

Bug 951566 - [Bluetooth][Bluedroid] Unknown.jpeg shown in notification after file transfer via Bluetooth, r=@dominickuo

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https://hg.mozilla.org/integration/gaia-central/rev/75a707f18897
Author: ian-liu <iliu@mozilla.com>
Desc: Bug 951566 - [Bluetooth][Bluedroid] Unknown.jpeg shown in notification after file transfer via Bluetooth
Bumping manifests a=b2g-bump