proxy: add more columns to parquet upload (#6405)

## Problem

Some fields were missed in the initial spec.

## Summary of changes

Adds a success boolean (defaults to false unless specifically marked as
successful).
Adds a duration_us integer that tracks how many microseconds were taken
from session start through to request completion.

proxy/src/serverless/sql_over_http.rs

@@ -497,6 +497,7 @@ async fn handle_inner(
             }
         };
 
+    ctx.set_success();
     ctx.log();
     let metrics = client.metrics();