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

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https://hg.mozilla.org/integration/gaia-central/rev/a91a7956eb49
Author: EragonJ <eragonj@eragonj.me>
Desc: Merge pull request #14564 from EragonJ/bug-948769

Bug 948769 - [Settings][DSDS] Default service ID should be a number

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https://hg.mozilla.org/integration/gaia-central/rev/302a148e42af
Author: EragonJ <eragonj@eragonj.me>
Desc: Bug 948769 - [Settings][DSDS] Default service ID should be a number

- make all settings from String to Number