[wasm] Implement System.Console.Clear

[campersau]

In #41184 (comment) it was mentioned that System.Console.Clear should be implemented since now it is not marked as UnsupportedOSPlatformAttribute("browser") but throws PlatformNotSupportedException.

runtime/src/libraries/System.Console/src/System/ConsolePal.WebAssembly.cs

Line 166 in 271f008

public static void Clear() => throw new PlatformNotSupportedException();

So this PR does that by using the same code pattern as in BrowserHttpClient:

runtime/src/libraries/System.Net.Http/src/System/Net/Http/BrowserHttpHandler/BrowserHttpHandler.cs

Line 32 in 271f008

private static readonly JSObject? s_fetch = (JSObject)System.Runtime.InteropServices.JavaScript.Runtime.GetGlobalObject("fetch");

runtime/src/libraries/System.Net.Http/src/System.Net.Http.csproj

Lines 722 to 724 in 271f008

	<ItemGroup Condition=" '$(TargetsBrowser)' == 'true'">
	<ProjectReference Include="$(LibrariesProjectRoot)System.Private.Runtime.InteropServices.JavaScript\src\System.Private.Runtime.InteropServices.JavaScript.csproj" />
	</ItemGroup>

Fixes mono/mono#19825

[ghost]

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[campersau]

Since Console.Clear might not be used that much, I can move the initialization into Clear itself if needed.

[lewing]

I think I'd prefer it happen in clear for now with a try catch that wraps the missing object exception just so we don't suddenly start throwing here if console is missing

[campersau]

In my testing System.Runtime.InteropServices.JavaScript.Runtime.GetGlobalObject did not throw an exception if the object does not exist, and just returns null.

try
{
    var abc = System.Runtime.InteropServices.JavaScript.Runtime.GetGlobalObject("abc");
    if (abc is null) Console.WriteLine("abc is null");
    else Console.WriteLine($"abc is {abc.GetType().FullName}");
}
catch (Exception ex)
{
    Console.WriteLine($"{ex.GetType().FullName}: {ex.Message}\n{ex.StackTrace}");
}

logged

abc is null

---

Calling Invoke("clear") would throw if the method does not exists:

System.Runtime.InteropServices.JavaScript.JSException: Error: Method: 'abc' not found for: '[object Object]'

Should this be catched and ignored?

[ghost]

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[lewing]

@campersau thanks again for another catch. We're considering some more extensive changes for console in 6 but this doesn't need to wait for that. I'm curious if this has any size impact.

[lewing]

The failures here appear to be from #43037

[lewing]

Failures are #43166 and unrelated to the change