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

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https://hg.mozilla.org/integration/gaia-central/rev/73305820b666
Author: Aleh Zasypkin <aleh.zasypkin@gmail.com>
Desc: Merge pull request #23726 from azasypkin/bug-1061215-remaining-chars-counter

Bug 1061215 - [Messages][Refactoring] Improve handling of remaining chars counter. r=julien

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https://hg.mozilla.org/integration/gaia-central/rev/52841a3a4dba
Author: Aleh Zasypkin <azasypkin@mozilla.com>
Desc: Bug 1061215 - [Messages][Refactoring] Improve handling of remaining chars counter. r=julien

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https://hg.mozilla.org/integration/gaia-central/rev/c8408a029524
Author: James Burke <jrburke@gmail.com>
Desc: Merge pull request #24321 from jrburke/bug1070895-email-search-enter

Bug 1070895 - Pressing ENTER in search box clears search and returns back to inbox r=asuth

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https://hg.mozilla.org/integration/gaia-central/rev/fa063efd37c6
Author: jrburke <jrburke@gmail.com>
Desc: Bug 1070895 - Pressing ENTER in search box clears search and returns back to inbox
Bumping manifests a=b2g-bump