fix(tracing): import APIError from scale_gp_beta public module (CI lint)

CI pyright reports reportPrivateImportUsage on
`from scale_gp_beta._exceptions import APIError` because the
`_exceptions` submodule is private. Re-export of `APIError` is
available at the package root, so use that instead.

Author: mohammadatallah-scale

src/agentex/lib/core/tracing/processors/sgp_tracing_processor.py

@@ -4,8 +4,7 @@
 from typing import Optional, override
 
 import scale_gp_beta.lib.tracing as tracing
-from scale_gp_beta import SGPClient, AsyncSGPClient
-from scale_gp_beta._exceptions import APIError
+from scale_gp_beta import APIError, SGPClient, AsyncSGPClient
 from scale_gp_beta.lib.tracing import create_span, flush_queue
 from scale_gp_beta.lib.tracing.span import Span as SGPSpan
 

tests/lib/core/tracing/processors/test_sgp_tracing_processor.py

@@ -406,7 +406,7 @@ async def test_shutdown_before_any_event_is_noop(self):
     async def test_apierror_triggers_retry_then_drops_batch_on_exhaustion(self):
         """`APIError` must be retried up to DEFAULT_RETRIES times. After
         exhaustion, the batch is dropped and the worker continues."""
-        from scale_gp_beta._exceptions import APIError
+        from scale_gp_beta import APIError
 
         processor, client = TestSGPAsyncTracingProcessorBatching._make_processor()