feat: subnet_ids validation

[jpluta]

What changes does your PR bring?

In a few words, describe what changes your commits make to the code.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• Chore (non-breaking change to the build process or auxiliary tools)
• New feature (non-breaking change which adds functionality)
• Documentation (Improvements or additions to documentation)
• Breaking change (fix or feature that would cause existing functionality not to work as expected)

References

Fixes:

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented on my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules