fix: clients/src/MvcCode/MvcCode.csproj to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-DOTNET-MICROSOFTIDENTITYMODELJSONWEBTOKENS-6148656
- https://snyk.io/vuln/SNYK-DOTNET-SYSTEMIDENTITYMODELTOKENSJWT-6148655

clients/src/MvcCode/MvcCode.csproj

@@ -7,7 +7,7 @@
 
 
     <ItemGroup>
-        <PackageReference Include="Microsoft.AspNetCore.Authentication.OpenIdConnect" Version="6.0.0"/>
+        <PackageReference Include="Microsoft.AspNetCore.Authentication.OpenIdConnect" Version="6.0.26"/>
 
         <PackageReference Include="OpenTelemetry"/>
         <PackageReference Include="OpenTelemetry.Exporter.Console"/>