build(deps): bump go.opentelemetry.io/otel/sdk (GoogleCloudPlatform#4160)

Bumps [go.opentelemetry.io/otel/sdk](https://github.com/open-telemetry/opentelemetry-go) from 1.38.0 to 1.40.0.
- [Release notes](https://github.com/open-telemetry/opentelemetry-go/releases)
- [Changelog](https://github.com/open-telemetry/opentelemetry-go/blob/main/CHANGELOG.md)
- [Commits](open-telemetry/opentelemetry-go@v1.38.0...v1.40.0)

---
updated-dependencies:
- dependency-name: go.opentelemetry.io/otel/sdk
  dependency-version: 1.40.0
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

benchmarks/latency-comparison/golang/go.mod

@@ -84,22 +84,21 @@ require (
 	github.com/tklauser/go-sysconf v0.3.12 // indirect
 	github.com/tklauser/numcpus v0.6.1 // indirect
 	github.com/yusufpapurcu/wmi v1.2.4 // indirect
-	github.com/zeebo/errs v1.4.0 // indirect
 	go.opencensus.io v0.24.0 // indirect
 	go.opentelemetry.io/auto/sdk v1.2.1 // indirect
 	go.opentelemetry.io/contrib/detectors/gcp v1.38.0 // indirect
 	go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.61.0 // indirect
 	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.61.0 // indirect
-	go.opentelemetry.io/otel v1.38.0 // indirect
+	go.opentelemetry.io/otel v1.40.0 // indirect
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.19.0 // indirect
-	go.opentelemetry.io/otel/metric v1.38.0 // indirect
-	go.opentelemetry.io/otel/sdk v1.38.0 // indirect
-	go.opentelemetry.io/otel/sdk/metric v1.38.0 // indirect
-	go.opentelemetry.io/otel/trace v1.38.0 // indirect
+	go.opentelemetry.io/otel/metric v1.40.0 // indirect
+	go.opentelemetry.io/otel/sdk v1.40.0 // indirect
+	go.opentelemetry.io/otel/sdk/metric v1.40.0 // indirect
+	go.opentelemetry.io/otel/trace v1.40.0 // indirect
 	golang.org/x/crypto v0.46.0 // indirect
 	golang.org/x/net v0.48.0 // indirect
 	golang.org/x/sync v0.19.0 // indirect
-	golang.org/x/sys v0.39.0 // indirect
+	golang.org/x/sys v0.40.0 // indirect
 	golang.org/x/text v0.32.0 // indirect
 	golang.org/x/time v0.14.0 // indirect
 	google.golang.org/genproto v0.0.0-20250603155806-513f23925822 // indirect