[CI] Run slow tests using .NET 10.

Author: vyazelenko

.github/workflows/slow.yml

@@ -34,7 +34,7 @@ jobs:
  strategy:
  matrix:
  java: [ '25' ]
- dotnet: [ '8.0.x' ]
+ dotnet: [ '10' ]
  env:
  DOTNET_SKIP_FIRST_TIME_EXPERIENCE: true
  DOTNET_CLI_TELEMETRY_OPTOUT: 1