Fixed DNS name generation

[lamaks]

Details

Fixed DNS name generation to conform to DNS name convention. Added .NET SDK availability check.

Pull request checklist

• [ ] Addresses an existing issue: Fixes #0000
• [ ] Added relevant unit test for your changes. (yarn test)
• [ ] Verified code coverage for the changes made. Check coverage report at: <rootDir>/test-results/unit/coverage
• [ ] Ran precheckin (yarn precheckin)
• [ ] Validated in an Azure resource group