chore(deps): Bump System.Collections.Immutable from 8.0.0 to 9.0.0 (#683)

Bumps [System.Collections.Immutable](https://github.com/dotnet/runtime) from 8.0.0 to 9.0.0.
- [Release notes](https://github.com/dotnet/runtime/releases)
- [Commits](dotnet/runtime@v8.0.0...v9.0.0)

---
updated-dependencies:
- dependency-name: System.Collections.Immutable
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

Client/Client.csproj

@@ -42,7 +42,7 @@
         <PackageReference Include="JsonSubTypes" Version="2.0.1" />
         <PackageReference Include="Microsoft.Extensions.ObjectPool" Version="9.0.0" />
         <PackageReference Include="Microsoft.Net.Http.Headers" Version="2.2.8" />
-        <PackageReference Include="System.Collections.Immutable" Version="8.0.0" />
+        <PackageReference Include="System.Collections.Immutable" Version="9.0.0" />
         <PackageReference Include="System.Configuration.ConfigurationManager" Version="9.0.0" />
         <PackageReference Include="System.Reactive" Version="6.0.1" />
     </ItemGroup>