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

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https://hg.mozilla.org/integration/gaia-1_4/rev/5cd61484ef25
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Merge pull request #18044 from etiennesegonzac/bug-992948-sysmsg-call-log

Bug 992948 - Use the telephony-call-ended sysmsg to record calls r=rik
(cherry picked from commit 04a7f8d951d1ed8bdbe5eaea75b3204792d24fa4)

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https://hg.mozilla.org/integration/gaia-1_4/rev/7d1794e68e9f
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Merge pull request #18049 from etiennesegonzac/bug-993018-place-new-call-activity

Bug 993018 - Replace the "place new call" postMessages with a WebActivity r=rik
(cherry picked from commit d2a70ab329a0f85a1a7fd38c7c9297abd763ee1e)
Bumping manifests a=b2g-bump