fix: Update logic for createdBy Tag

[NirajC-Microsoft]

Purpose

This pull request updates the logic for setting the createdBy parameter in the Bicep infrastructure template. The change improves how the value is determined by handling cases where userPrincipalName may not be present.

Parameter handling improvement:

• Changed the createdBy parameter to check for the existence of userPrincipalName in the deployer() object. If present, it uses the username portion; otherwise, it falls back to using the objectId. This ensures the tag is always populated with a meaningful value.
• ...

Does this introduce a breaking change?

• Yes
• No

Golden Path Validation

• I have tested the primary workflows (the "golden path") to ensure they function correctly without errors.

Deployment Validation

• I have validated the deployment process successfully and all services are running as expected with this change.

What to Check

Verify that the following are valid

• ...

Other Information