Bumping gaia.json for 4 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/4544fae7317b
Author: evanxd <itoyxd@gmail.com>
Desc: Merge pull request #19538 from evanxd/bug-1014475

Bug 1014475 - Re-enable the disabled marionette tests for System app

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https://hg.mozilla.org/integration/gaia-central/rev/ce30a72fa777
Author: Evan Xd <itoyxd@gmail.com>
Desc: Bug 1014475 - Close app without using marionette-apps module

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https://hg.mozilla.org/integration/gaia-central/rev/3f60d1345003
Author: Albert <acperez@tid.es>
Desc: Merge pull request #19465 from acperez/bug-1013611

Bug 1013611: Enable app:// for resources in single variant build process

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https://hg.mozilla.org/integration/gaia-central/rev/4196c711afcc
Author: Albert <acperez@tid.es>
Desc: Bug 1013611: Enable app:// for resources in single variant build process
Bumping manifests a=b2g-bump