Macro handle_schema_err

macro_rules! handle_schema_err {
    ($result:expr) => { ... };
}

Handles schema errors, transforming a Result into an Option.

• If the input is Ok(v), returns Some(v)
• If the input is Err(err) and the error status code is TableNotFound or TableColumnNotFound, returns None (ignoring these specific errors)
• If the input is Err(err) with any other error code, directly returns a PrometheusJsonResponse::error.