[browser] Marshalling of resolved Tasks/promises is not resolved in JS/C#

[ilonatommy]

The PR solves the problem with void Task marshalling. Fixes #104772.

• Added lib test for javascript calling a method with return Task type in .net 9.0 preview6, the returned promise is always in pending state #104772
• C# to JS in net8.0.7 returned Promise is resolved. Success. -> regression
• Added lib test for JSImport that is the same as the issue but with opposite marshalling direction.

cc @pavelsavara

Might be connected: #95411

[pavelsavara]

WBT is too heavy weight integration test for this. Let's add test to src\libraries\System.Runtime.InteropServices.JavaScript\tests\System.Runtime.InteropServices.JavaScript.UnitTests\System\Runtime\InteropServices\JavaScript\JSImportTest.cs instead

[ilonatommy]

ST

MT JSImport

MT JSExport - disabled, re-run with update.