[monitor opentelemetry exporter] Handle ServiceResponseError as retryable to prevent telemetry loss

[hectorhdzg]

ServiceResponseError (e.g. read timeout) was not caught by the exporter's _transmit method. Since ServiceResponseError and ServiceRequestError are sibling classes (both extend AzureError directly), a read timeout fell through to the generic 'except Exception' handler, which marked the batch as FAILED_NOT_RETRYABLE — permanently dropping the telemetry instead of persisting it to local storage for retry.

This change adds ServiceResponseError to the import and catch chain, treating it as FAILED_RETRYABLE so that envelopes are written to disk and retried on the next successful export cycle, consistent with the existing ServiceRequestError handling and the azure-core docstring which states these errors 'can be retried for idempotent or safe operations'.

[Copilot]

Pull request overview

This PR fixes a telemetry-loss bug in the Azure Monitor OpenTelemetry Exporter. Previously, a ServiceResponseError (e.g. a read timeout) fell through to the generic except Exception handler in BaseExporter._transmit(), which marked the batch as FAILED_NOT_RETRYABLE and permanently dropped the telemetry. The change adds a dedicated ServiceResponseError handler that classifies it as FAILED_RETRYABLE, so envelopes are persisted to local offline storage and retried, consistent with the existing ServiceRequestError handling and the azure-core guidance that these errors are safe to retry.

Changes:

• Add ServiceResponseError to the import and exception chain in _transmit(), treating it as FAILED_RETRYABLE and mirroring the existing statsbeat and customer-sdkstats tracking done for ServiceRequestError.
• Add unit tests for the retryable result and statsbeat exception counting on ServiceResponseError.
• Add a customer-sdkstats test verifying track_retry_items is invoked on ServiceResponseError.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
azure/monitor/opentelemetry/exporter/export/_base.py	Adds ServiceResponseError import and a new retryable except branch (with statsbeat + customer-sdkstats tracking) placed before the generic Exception handler.
tests/test_base_exporter.py	Adds test_transmit_response_error and test_transmit_response_error_statsbeat mirroring the existing ServiceRequestError tests.
tests/test_base_customer_sdkstats.py	Adds test_transmit_service_response_error_customer_sdkstats_track_retry_items verifying retry tracking on ServiceResponseError.

Note: Consider adding a CHANGELOG.md entry under the unreleased 1.0.0b56 "Bugs Fixed" section, since this package maintains per-PR changelog entries for bug fixes.