Integrate 3/18 nightly RN build.

[rectified95]

Commits: facebook/react-native@d477f80...cfb5b5e

Closes #7309 by pulling in the updated MapBuffer.cpp
Closes #7289 by pulling in an update to Yoga.cpp

Issues discovered during this integration, not necessarily caused by this batch, though still recent regressions:
#7557
#7556
#7555
#7554

Microsoft Reviewers: Open in CodeFlow

[NickGerleman]

Looking through the upstream commits, I think we might have a new native constant localeIdentifier in NativeI18nManager. Is this something we should add?

[NickGerleman]

Overall looks good, but see comments about restoring the Windows custom DatePicker page, along with whether we need to do anything with a new native constant.

[rectified95]

@NickGerleman Interestingly, the constant is already in I18nManagerModule.cpp

react-native-windows/vnext/Microsoft.ReactNative/Modules/I18nManagerModule.cpp

Line 72 in a0e1e99

provider.Add(L"localeIdentifier", locale);

[NickGerleman]

@NickGerleman Interestingly, the constant is already in I18nManagerModule.cpp

react-native-windows/vnext/Microsoft.ReactNative/Modules/I18nManagerModule.cpp

Line 72 in a0e1e99

provider.Add(L"localeIdentifier", locale);

Ooh neat. It might have been that upstream was refining flow types to capture it. Always great to discover we don't have extra work to do 😂.

[ghost]

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[asklar]

signing off - are the newly discovered issues regressions on our side that we're only finding now, or regressed by this new ingestion? either way it would be good to tag them accordingly so we can track.