test : add unit tests for get_delivery_configuration in notification_service

[tmdeveloper007]

Summary of What Needs to be Done:

Add unit tests for get_delivery_configuration in backend/secuscan/notification_service.py. This function returns a static configuration dict for webhook delivery timeouts and retry settings. It currently has no test coverage.

The function returns:

{
    "webhook_timeout_seconds": _WEBHOOK_TIMEOUT_SECONDS,
    "webhook_connect_timeout_seconds": _WEBHOOK_CONNECT_TIMEOUT_SECONDS,
    "max_retries": 0,
    "backoff_factor_seconds": 0.0,
}

Changes that Need to be Made:

Create testing/backend/unit/test_notification_service_delivery_config.py with:

• test_returns_expected_keys: verify the dict contains webhook_timeout_seconds, webhook_connect_timeout_seconds, max_retries, backoff_factor_seconds
• test_values_are_correct_types: webhook_timeout_seconds and webhook_connect_timeout_seconds are positive integers; max_retries is 0; backoff_factor_seconds is 0.0
• test_returns_new_dict_each_call: calling the function twice returns equal-but-distinct dict objects (no shared mutable state)

Import get_delivery_configuration from backend.secuscan.notification_service.

Impact that it would Provide:

• Reliability: the configuration values are used by the delivery pipeline — tests prevent accidental regressions
• Coverage: brings this production module line under test

Note: This task is being handled by tmdeveloper007 — please assign to that account when picking it up.