fix(data-drains): drain datadog and bigquery probe success bodies

Same undici keep-alive issue as the prior fixes: postWithRetries
returned the Response on success without draining (callers only read
headers); the BigQuery `test()` probe returned without consuming the
body. Both now drain before returning.

Author: waleedlatif1

apps/sim/lib/data-drains/destinations/bigquery.ts

@@ -304,6 +304,8 @@ export const bigqueryDestination: DrainDestination<
       const text = await response.text().catch(() => '')
       throw new Error(`BigQuery probe failed (HTTP ${response.status}): ${text}`)
     }
+    /** Drain the success body so undici can return the socket to the keep-alive pool. */
+    await response.text().catch(() => '')
   },
 
   openSession({ config, credentials }) {

apps/sim/lib/data-drains/destinations/datadog.ts

@@ -172,7 +172,11 @@ async function postWithRetries(input: PostInput): Promise<Response> {
       logger.debug('Datadog request failed', { attempt, error: toError(error).message })
     }
     if (response) {
-      if (response.ok) return response
+      if (response.ok) {
+        /** Drain the success body so undici can return the socket to the keep-alive pool. Headers remain readable after consumption. */
+        await response.text().catch(() => '')
+        return response
+      }
       if (!isRetryableStatus(response.status)) {
         const text = await response.text().catch(() => '')
         throw new Error(`Datadog responded with HTTP ${response.status}: ${text}`)