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

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https://hg.mozilla.org/integration/gaia-central/rev/1bfa9e10dc2b
Author: Salvador de la Puente González <salva@unoyunodiez.com>
Desc: Merge pull request #12387 from leob2g/Bug_915992_Changing_default_configuration_to_Postpaid

[Cost Control] Bug_915992_Changing_default_config_to_Postpaid r=lodr

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https://hg.mozilla.org/integration/gaia-central/rev/ebc57c722136
Author: sarath27.vs <sarath27.vs@lge.com>
Desc: Changing default config to Postpaid