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

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https://hg.mozilla.org/integration/gaia-central/rev/6890cdf5807b
Author: Yi-Fan Liao <yliao@mozilla.com>
Desc: Merge pull request #23993 from begeeben/1051100_multiple_lines_are_displayed

Bug 1051100 - [B2G] [Homescreen] Multiple lines are displayed when moving apps to the bottom of the Homescreen, r=Chris

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https://hg.mozilla.org/integration/gaia-central/rev/12088d6099b0
Author: Yi-Fan Liao <begeeben@gmail.com>
Desc: Bug 1051100 - [B2G] [Homescreen] Multiple lines are displayed when moving apps to the bottom of the Homescreen

* Before adding a horizontal divider in edit mode on the vertical homescreen, check if one is needed.

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https://hg.mozilla.org/integration/gaia-central/rev/4f1446fad1de
Author: Min-Zhong "John" Lu <jlu@mozilla.com>
Desc: Merge pull request #24205 from mnjul/bug_1067264_remove_blur_delay_kb_app

Bug 1067264 - Remove delay of layout/IME deactivation in built-in keyboard app as a follow-up of bug 1057898. r=timdream

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https://hg.mozilla.org/integration/gaia-central/rev/c4d96f9b65c6
Author: John Lu [:mnjul] <jlu@mozilla.com>
Desc: Bug 1067264 - Remove delay of layout/IME deactivation in built-in keyboard app as a follow-up of bug 1057898

- The need for delaying deactivation is no longer needed after bug 1057898 and bug 1067266.
- StateManager.DEACTIVATE_DELAY is removed.
- In deactivation, propogatation the triggering of setTimeout callback (of the delay), in forms of resolution of Promises, is removed. Async codes made into sync codes.
- Unit test cases regarding rapid activation after deactivation, and vice versa, are removed, since the behavior should now be guarded by Gecko.
Bumping manifests a=b2g-bump