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

========

https://hg.mozilla.org/integration/gaia-central/rev/482809f5cff7
Author: steveck-chung <schung@mozilla.com>
Desc: Merge pull request #17317 from ankit93040/943976_SMS/MMS__Attaching_Video_MMS_Prompts_Wrong_Error_Message

Bug 943976: Attaching_Video_MMS_Prompts_Wrong_Error_Message, r=schung

========

https://hg.mozilla.org/integration/gaia-central/rev/81784c3e3095
Author: ankit.agrawal <ankit.agrawal@lge.com>
Desc: 943976_Attaching_Video_MMS_Prompts_Wrong_Error_Message
Bumping manifests a=b2g-bump