Fix app restart on split screen (Android)

[Somena1]

This commit fixes app restart on split screen and screen resize
issue #5068

[gnprice]

Thanks @Somena1 for tracking this down! Will be great to have this fix in.

One tiny comment below. Other than that, the commit history needs some cleaning-up to meet our style. I described this with more details in a chat thread; happy to answer questions there or in the #git help stream.

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I tried this out empirically, and it worked great.

The main question was whether the app would successfully handle those changes. Basically this line of the Android manifest is making an assurance to the system that the app is prepared to handle these changes; docs here:
https://developer.android.com/guide/topics/manifest/activity-element#config
When the system doesn't get that assurance, it just restarts the app from scratch to be sure.

And empirically the app indeed does just fine when we add those assurances and then go ahead and switch to split-screen mode, or resize the app's portion of the split screen. That layer of things is basically all RN's job, so RN is handling this just fine -- we just haven't been letting the system know that we're ready to do so.

So that means this change almost certainly should also go into React Native upstream, in their template app. Here's an upstream report of the issue: facebook/react-native#25040
The author of that issue closed it after learning they could make this change in their own app, but it really should go in the template app so that all future RN apps benefit. If you'd like to send a version of this PR to RN upstream too, that would also be a nice contribution.

[Somena1]

@gnprice I've been been able to fix the author, I still can't resolve the merge commit. I don't know if using the script from tools folder will break the branch.

[gnprice]

Thanks for the revision!

I still can't resolve the merge commit. I don't know if using the script from tools folder will break the branch.

Hmm, I don't know what script you're referring to. Please post in the #git help stream, and describe what you've tried and what results you've gotten. Then we can help you there.

[Somena1]

Okay then, I'll head to the #git help stream