Blazor WebAssembly - handle unsupported properties properly

[rose-a]

In #274 we've added a workaround for unsupported properties in WASM which swallows the PlatformNotSupported exceptions.
We should add proper guards to avoid execution this part of the code completely when running on WebAssembly.

@bjorg, I've found this answer in a GitHub issue on "detecting if the code runs in WASM".

Could you please try if RuntimeInformation.IsOSPlatform(OSPlatform.Create("WEBASSEMBLY")) correctly detects your code running in WebAssembly? This way we could purposely avoid accessing these properties without swallowing exceptions...

Seems that from .NET 5 on we'll get a OperatingSystem.IsBrowser() method to do just this, according to this article...

[bjorg]

I saw the announcement for OperatingSystem.IsBrowser(), but I was not aware of RuntimeInformation.IsOSPlatform(OSPlatform.Create("WEBASSEMBLY")).

I'm happy to test it and see if it works as expected. The expectation being that unsupported properties are simply ignored and not set, correct?

[rose-a]

yeah, I'm thinking something like

if(!RuntimeInformation.IsOSPlatform(OSPlatform.Create("WEBASSEMBLY"))){
    _clientWebSocket.Options.ClientCertificates = ((HttpClientHandler)Options.HttpMessageHandler).ClientCertificates;
    _clientWebSocket.Options.UseDefaultCredentials = ((HttpClientHandler)Options.HttpMessageHandler).UseDefaultCredentials;
}

[bjorg]

Here you go: #283

Please verify that I didn't break anything for other runtime targets.