Make the ClickHouse exporter request timeout configurable #2900

Summary

The OpAMP-managed and standalone OpenTelemetry Collector configurations hardcode a 5s request timeout for both ClickHouse exporters (clickhouse and clickhouse/rrweb). Deployments whose inserts legitimately need longer to be acknowledged cannot tune that deadline without replacing generated configuration.

Impact

The exporter cancels an insert attempt when the five-second context deadline expires even if ClickHouse is configured to allow the operation to run longer. This can cause avoidable export failures and retries under heavier ingestion or materialized-view workloads.

Affected configuration paths

• OpAMP-generated collector configuration in the HyperDX API
• Standalone collector configuration
• Both clickhouse and clickhouse/rrweb exporters

Expected behavior

Allow deployments to configure the exporter request timeout while preserving 5s as the default for backward compatibility.

Proposed fix

Read HYPERDX_OTEL_EXPORTER_TIMEOUT through the collector's supported environment interpolation in all four exporter definitions:

timeout: '${env:HYPERDX_OTEL_EXPORTER_TIMEOUT:-5s}'

Add regression coverage for both exporters in the OpAMP-generated configuration and record patch releases for the affected packages.

An implementation is available in #2899.