docs(telemetry): drop sampling_ratio from workload sample configs

Head sampling is fixed at 1.0 and not configurable; remove the
sampling_ratio line from the benchmark, full-validation, and validator
config-template sample blocks.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

docker/telemetry/workload/benchmark.sh

@@ -145,7 +145,6 @@ enabled=1
 service_instance_id=bench-node-${i}
 endpoint=http://localhost:4318/v1/traces
 exporter=otlp_http
-sampling_ratio=1.0
 batch_size=512
 batch_delay_ms=2000
 max_queue_size=2048

docker/telemetry/workload/run-full-validation.sh

@@ -285,7 +285,6 @@ enabled=1
 service_instance_id=validator-${i}
 endpoint=http://localhost:4318/v1/traces
 exporter=otlp_http
-sampling_ratio=1.0
 batch_size=512
 batch_delay_ms=2000
 max_queue_size=2048

docker/telemetry/workload/xrpld-validator.cfg.template

@@ -64,7 +64,6 @@ enabled=1
 service_instance_id=validator-{{NODE_INDEX}}
 endpoint={{OTEL_ENDPOINT}}
 exporter=otlp_http
-sampling_ratio=1.0
 batch_size=512
 batch_delay_ms=2000
 max_queue_size=2048