confluent_kafka span attribute info error

[FarmerChillax]

current messaging.operation field val is receive when sending messages, but expect val is send.

env info:

• otel.scope.name: opentelemetry.instrumentation.confluent_kafka
• otel.scope.version: 0.43b0 - 0.51b0
• Python version: 3.7 - 3.9

[alliasgher]

Opened #4435 for this.