Improve sample: safer argument parsing and clearer delay

[ivanPeshterskii]

Description

This PR improves the readability and robustness of the code sample.

Changes made

• Replaced Convert.ToInt32 with int.TryParse to prevent exceptions when invalid input is provided.
• Simplified the command-line argument check from args.Length is not 0 to args.Length > 0 for better clarity.
• Replaced TimeSpan.FromMilliseconds(1_000) with TimeSpan.FromSeconds(1) to improve readability.
• Slightly refactored the counter increment for better readability in beginner-focused documentation.

These changes make the sample safer and easier to understand, especially for developers who are new to C#.

Motivation

The previous version could throw an exception if a non-numeric argument was passed. Using int.TryParse ensures the example behaves more safely and demonstrates a recommended pattern for parsing user input.