New Tab Page: when initialized from JS, force send updated data

[petemill]

Fix brave/brave-browser#5249

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Test Plan:

Specified in issue

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[imptrx]

I am testing this on a debug build so everything happens in slow motion 🐌Current behavior is that NTP flashes with erroneous preferences and then re-renders correctly within a quarter of a second.
This will probably not be as apparent in a release build but just a heads up

also just realized we are getting background images twice:

[petemill]

ok good to know, thanks @imptrx - I'll test with a debug build too then. I think we should just go ahead and do the proper fix then. I'll close this and experiment.