Bumping gaia.json for 1 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-1_3/rev/15b1d1141db1
Author: David Flanagan <dflanagan@mozilla.com>
Desc: Merge pull request #20712 from davidflanagan/bug1026846

Bug 1026846: require the type parameter for FL app view activity r=amac
Bumping manifests a=b2g-bump