chore: Bump Microsoft.Orleans.TestingHost from 10.3.1 to 10.4.0

---
updated-dependencies:
- dependency-name: Microsoft.Orleans.TestingHost
  dependency-version: 10.4.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

Directory.Packages.props

@@ -19,7 +19,7 @@
         <PackageVersion Include="Microsoft.Orleans.Sdk" Version="10.3.1" />
         <PackageVersion Include="Microsoft.Orleans.Serialization.Abstractions" Version="10.3.1" />
         <PackageVersion Include="Microsoft.Orleans.Server" Version="10.3.1" />
-        <PackageVersion Include="Microsoft.Orleans.TestingHost" Version="10.3.1" />
+        <PackageVersion Include="Microsoft.Orleans.TestingHost" Version="10.4.0" />
         <PackageVersion Include="Microsoft.Testing.Extensions.CodeCoverage" Version="18.11.2" />
         <PackageVersion Include="OpenTelemetry.Extensions.Hosting" Version="1.19.0" />
         <PackageVersion Include="Shouldly" Version="4.3.0" />