Bumping gaia.json for 4 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/73e6bf9d0000
Author: Staś Małolepszy <stas@mozilla.com>
Desc: Merge pull request #24810 from stasm/1043643-use-shared-mockl10n

Bug 1043643 - Migrate tests to use shared mock_l10n. r=stas

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https://hg.mozilla.org/integration/gaia-central/rev/db77f3e0676c
Author: Aniket Jain <aniketisin@bitbucket.org>
Desc: Bug 1043643 - Migrate most tests to shared mock_l10n. r=stas

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https://hg.mozilla.org/integration/gaia-central/rev/18af3d35fee0
Author: Rudy Lu <me@rudy.lu>
Desc: Merge pull request #24816 from comoyo/bug1007547

Bug 1007547 - Add keyboard and wordlist for Basque.
r=janjongboom.

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https://hg.mozilla.org/integration/gaia-central/rev/ed6c1843f8eb
Author: Igor Leturia e-gor <ileturia@gmail.com>
Desc: Bug 1007547 - Add keyboard and wordlist for Basque
Bumping manifests a=b2g-bump