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

========

https://hg.mozilla.org/integration/gaia-central/rev/2abf97674c6a
Author: James Lal <james@lightsofapollo.com>
Desc: Merge pull request #12279 from lightsofapollo/disable-modify-event-view

disable modify_event_test a=test-only

========

https://hg.mozilla.org/integration/gaia-central/rev/b12465654e88
Author: James Lal <james@lightsofapollo.com>
Desc: disable modify_event_test a=test-only