replace manual field assertions with CAMARA schema validation

Replace manual field assertions with CAMARA Pydantic schema validation across
multiple EdgeCloud e2e tests for improved maintainability and compliance.

Changes:
- test_get_edge_cloud_zones: Add CAMARA EdgeCloudZone schema validation and logical validation for expected zone
- test_onboard_app: Replace manual appId check with SubmittedApp schema validation
- test_get_onboarded_app: Replace manual field checks with AppManifest schema validation
- test_get_all_onboarded_apps: Replace manual field assertions with AppManifest schema validation + logical validation
- test_get_all_deployed_apps: Replace manual field assertions with AppInstanceInfo schema validation
- test_get_deployed_app: Replace manual field checks with AppInstanceInfo schema validation
- app_instance_id fixture: Add CAMARA schema validation for deployment response
- Reduce timer from 30s to 10s for faster test execution

Benefits:
- Future-proof tests against CAMARA specification changes
- Improved error messages when schema validation fails
- Cleaner, more maintainable test code
- Combines schema compliance with logical business validation
- Ensures all API responses are CAMARA-compliant