Remove incorrect lettuce-4.0 db.statement attribute

[trask]

following #4152, and removing db.statement since it's not really capturing db.statement

(note: lettuce-5.0 and lettuce-5.1 do capture db.statement correctly, I looked and it wasn't straight forward to port that back to lettuce-4.0)

[trask]

Hm, but db.statement is marked required, so maybe existing behavior is better?

Required if applicable and not explicitly disabled via instrumentation configuration.

https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/trace/semantic_conventions/database.md#call-level-attributes

[trask]

/easycla

[mateuszrzeszutek]

In case of lettuce 4.0 we really can't extract the statement, the library doesn't allow doing that. I think it's probably better not to set the statement if we can't get the real value.

[trask]

I think it's probably better not to set the statement if we can't get the real value.

👍

also, I just noticed this part of the spec that I missed previously:

db.operation | Required, if db.statement is not applicable.