/p:Configuration must use "Release" instead of "release" (dotnet#40816)

I am not very familiar with Unix so I was not aware why I was having below error:
```
/home/jozky/runtime/.dotnet/sdk/5.0.100-preview.8.20362.3/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.Sdk.FrameworkReferenceResolution.targets(379,5): error NETSDK1112: The runtime pack for Microsoft.NETCore.App.Runtime.browser-wasm was not downloaded. Try running a NuGet restore with the RuntimeIdentifier 'browser-wasm'. [/home/jozky/runtime/src/libraries/System.IO.FileSystem/tests/System.IO.FileSystem.Tests.csproj]
```

I tried running `dotnet restore --runtime browser-wasm` as suggested by the error but that didn't help.
The correct thing to do was to pass `Release` (with upper case R) to `Configuration` parameter.

cc @safern

docs/workflow/testing/libraries/testing-wasm.md

@@ -35,14 +35,14 @@ and even run tests one by one for each library:
 ### Running individual test suites
 The following shows how to run tests for a specific library
 ```
-./dotnet.sh build /t:Test src/libraries/System.AppContext/tests /p:TargetOS=Browser /p:TargetArchitecture=wasm /p:Configuration=release
+./dotnet.sh build /t:Test src/libraries/System.AppContext/tests /p:TargetOS=Browser /p:TargetArchitecture=wasm /p:Configuration=Release
 ```
 
 ### Running tests using different JavaScript engines
 It's possible to set a JavaScript engine explicitly by adding `/p:JSEngine` property: 
 
 ```
-./dotnet.sh build /t:Test src/libraries/System.AppContext/tests /p:TargetOS=Browser /p:TargetArchitecture=wasm /p:Configuration=release /p:JSEngine=SpiderMonkey
+./dotnet.sh build /t:Test src/libraries/System.AppContext/tests /p:TargetOS=Browser /p:TargetArchitecture=wasm /p:Configuration=Release /p:JSEngine=SpiderMonkey
 ```
 
 At the moment supported values are: