fix definition object properties

[thecomalley]

Pull Request Template

Description

This PR fixes the issue preventing policy objects to be passed into the definition module (rather than loading from a file), this is useful for when Terraform generates the policy definition eg using templatefile()

Fixes #79

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

• tested example in modules/definition/README.md under "You will also be able to supply object properties at runtime such as:"
• added use case to examples/definitions.tf to be tested during actions

Test Configuration:

• Module Version: 2.8.0
• Terraform Version: v1.4.6
• AzureRM Provider Version: v3.56.0

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have checked my code and corrected any misspellings