Add telemetry event for auto ep selection (#25243)
This pull request introduces telemetry enhancements for logging
execution provider (EP) auto-selection events in ONNX Runtime. The
changes include adding new methods to log EP selection data, updating
classes to support session ID retrieval, and integrating telemetry
logging into the session provider policy context.
### Telemetry Enhancements:
* **Added `LogAutoEpSelection` Method**: Introduced a new virtual method
in `Telemetry` and its override in `WindowsTelemetry` to log
session-specific EP auto-selection data, including requested and
available EP IDs and selection policies.
### Session ID Support:
* **Added `GetCurrentSessionId` Method**: Added a method to
`InferenceSession` to retrieve the current session ID, enabling
session-specific telemetry logging.
### Integration with Provider Policy Context:
* **Telemetry Logging in EP Selection**: Integrated telemetry logging
into `ProviderPolicyContext::SelectEpsForSession`, capturing requested
and available EP IDs, along with the selection policy type, and invoking
the telemetry provider's `LogAutoEpSelection` method.
