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

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https://hg.mozilla.org/integration/gaia-1_4/rev/52454024efa3
Author: Arthur Chen <crh0716@gmail.com>
Desc: Bug 988148 - Hide the mobile connection state if it is emergency calls only and not primary sim

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https://hg.mozilla.org/integration/gaia-1_4/rev/e4ed78c14ad8
Author: Dominic Kuo <dkuo@mozilla.com>
Desc: Merge pull request #17499 from dominickuo/bug-982540

Bug 982540 - [Music] Recover the status to PLAYING after the player is resumed from the mozinterrupend event, r=jimporter
Bumping manifests a=b2g-bump