Bump System.Diagnostics.DiagnosticSource

Bumps the dotnet group in /docs/core/diagnostics/snippets/Metrics with 1 update: [System.Diagnostics.DiagnosticSource](https://github.com/dotnet/runtime).


Updates `System.Diagnostics.DiagnosticSource` from 9.0.3 to 9.0.4
- [Release notes](https://github.com/dotnet/runtime/releases)
- [Commits](dotnet/runtime@v9.0.3...v9.0.4)

---
updated-dependencies:
- dependency-name: System.Diagnostics.DiagnosticSource
  dependency-version: 9.0.4
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: dotnet
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

docs/core/diagnostics/snippets/Metrics/metric-instr.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
@@ -9,7 +9,7 @@
 
   <ItemGroup>
     <PackageReference Include="OpenTelemetry.Exporter.Prometheus.HttpListener" Version="1.6.0-rc.1" />
-    <PackageReference Include="System.Diagnostics.DiagnosticSource" Version="9.0.3" />
+    <PackageReference Include="System.Diagnostics.DiagnosticSource" Version="9.0.4" />
   </ItemGroup>
 
 </Project>