fix: Error: "An invalid IP address was specified."

[eddiewhho]

This pull request improves the robustness and accuracy of subnet mask extraction and calculation in both AzGovVizParallel.ps1 and processNetwork.ps1. The main focus is on correctly handling subnet prefixes, validating input, and providing better error handling to prevent runtime issues during IP address calculations.

Subnet mask extraction and validation improvements:

• Updated the method for extracting the subnet mask from AddressPrefix to correctly handle both single and double digit prefixes using a split operation instead of substring, making the code more reliable. [1] [2]
• Added validation for the extracted subnet prefix to ensure it is a valid integer between 0 and 32. If the prefix is invalid, the code now logs a warning and skips subnet mask calculation, preventing potential errors. [1] [2]

Error handling enhancements:

• Wrapped the subnet mask calculation logic in a try-catch block. If an exception occurs (e.g., due to invalid input), a warning is logged and the subnet mask and range are set to "Error", improving the script's resilience. [1] [2]

[eddiewhho]

@microsoft-github-policy-service agree

[jtracey93]

@JulianHayward for your review