CID-3381: Validate Env variables presence

[mohamedlajmileanix]

🛠 Changes made

Validate Env variables presence and avoid BeanCreationException

✨ Type of change

Please delete the options that are not relevant.

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

🧪 How Has This Been Tested?

• should pass when all properties are valid
• should throw exception when GitHubEnterpriseProperties are missing
• should throw exception when LeanIXProperties are missing

🏎 Checklist:

• My code follows the style guidelines
• I have performed a self-review of my own code
• My commit message clearly reflects the changes made
• Assigned the appropriate labels (version, PR type, etc.)

[github-actions]

LeanIX GitHub Agent Code Coverage

File	Coverage [61.62%]	🍏
AgentSetupValidation.kt	61.62%	🍏

Total Project Coverage	71.28%	🍏