fix: Networking vpc_config AttributeError and telemetry region fallba…

[aviruthen]

Issue #, if available:

Fixes two bugs:

1. AttributeError: 'Networking' object has no attribute 'vpc_config' — ModelBuilder._initialize_network_config() directly accesses self.network.vpc_config, but the Networking class (from sagemaker.core.training.configs) doesn't have that attribute. The else branch correctly handles Networking by reading subnets/security_group_ids directly, but execution never reaches it.
2. Telemetry uses us-west-2 despite region override — The _telemetry_emitter decorator on @classmethod methods (like from_jumpstart_config) resolves args[0].sagemaker_session from the class descriptor (which is None), then falls back to a hardcoded us-west-2 default session. Customers with restricted network environments see timeouts on sts.us-west-2.amazonaws.com and sm-pysdk-t-us-west-2.s3.us-west-2.amazonaws.com.

Description of changes:

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