💡 Feature Request - APIM missing DDOS recommendation check

## Describe the solution you'd like

I recently went through a resiliency review where I found out my customer did not configure APIM DDOS protection. Their APIM was not configured with vnet-injected and therefore Azure DDOS protection could not be enabled on their APIM instances. In my customer case, there are 2 mission critical applications (including their e-commerce web site) leveraging this API server and this is clearly a potential resiliency weakness that should be raised through APRL to be consistent with other DDOS recommendation in the library.
Reference : https://learn.microsoft.com/en-us/azure/api-management/protect-with-ddos-protection

## Describe alternatives you've considered

NA, we need a rule that detect APIM configured without vnet injection and ensure customer there is no way to enable DDOS protection

## Additional context

Add any other context or screenshots about the feature request here. 📷