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

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https://hg.mozilla.org/integration/gaia-1_4/rev/3bfdd47ea180
Author: Jan Jongboom <janjongboom@gmail.com>
Desc: Merge pull request #18076 from comoyo/bug993367

Bug 993367 - Stop reflowing on updateTargetWindowHeight. r=RudyL

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https://hg.mozilla.org/integration/gaia-1_4/rev/684e20016da6
Author: steveck-chung <schung@mozilla.com>
Desc: Merge pull request #18113 from steveck-chung/bug-988772

Bug 988772 - [tarako][buri] sometimes contact index shows nothing when tap on a index. r=arcturus.
Bumping manifests a=b2g-bump