Bump go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc from 0.40.0 to 1.23.1 in /examples/demo/client

Bump go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc from 0.40.0 to 1.23.1 in /examples/demo/client #8290