Address System.Net.Http.WinHttpHandler's nullable warnings targeting .NETCoreApp

[ViktorHofer]

When adding a NetCoreAppCurrent TFM to System.Net.Http.WinHttpHandler, more than 100 nullable warnings pop up that would need to be addressed.

Meanwhile the <Nullable> setting for NetCoreAppCurrent is set to annotations only, to avoid the warnings in the build.

Related: #54012

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Issue Details

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When adding a NetCoreAppCurrent TFM to System.Net.Http.WinHttpHandler, more than 100 nullable warnings pop up that would need to be addressed.

Meanwhile the <Nullable> setting for NetCoreAppCurrent is set to annotations only, to avoid the warnings in the build.

Related: #54012

Author:	ViktorHofer
Assignees:	-
Labels:	area-System.Net.Http
Milestone:	-