receive: enable ExportCreatedMetric in OTLP translator

Without ExportCreatedMetric, the StartTimeUnixNano field on OTLP
counters and histograms was silently dropped during translation to
Prometheus remote write. This broke counter reset detection for
downstream systems that rely on the _created timestamp to distinguish
a genuine counter reset from a fresh series.

Setting ExportCreatedMetric: true in the otlptranslator.Settings causes
the translator to emit a <metric>_created series carrying the
StartTimeUnixNano value, matching the behaviour described in the
Prometheus exposition format spec.

Fixes #8637

Signed-off-by: Ali <alliasgher123@gmail.com>

Author: alliasgher

pkg/receive/handler_otlp.go

@@ -161,6 +161,10 @@ func (h *Handler) convertToPrometheusFormat(ctx context.Context, pmetrics pmetri
 		AddMetricSuffixes:         true,
 		DisableTargetInfo:         !h.options.OtlpEnableTargetInfo,
 		PromoteResourceAttributes: h.options.OtlpResourceAttributes,
+		// ExportCreatedMetric preserves StartTimeUnixNano from OTLP as a
+		// _created timestamp, enabling correct counter reset detection by
+		// downstream Prometheus-compatible systems.
+		ExportCreatedMetric: true,
 	}
 
 	annots, err := converter.FromMetrics(ctx, pmetrics, settings)