fix: include error property in xhr and fetch callbacks

Author: logaretm

packages/browser/src/tracing/request.ts

@@ -343,6 +343,7 @@ function xhrCallback(
 
       onRequestSpanEnd?.(span, {
         headers: createHeadersSafely(parseXhrResponseHeaders(xhr as XMLHttpRequest & SentryWrappedXMLHttpRequest)),
+        error: handlerData.error,
       });
 
       // eslint-disable-next-line @typescript-eslint/no-dynamic-delete

packages/core/src/fetch.ts

@@ -160,6 +160,7 @@ export function _callOnRequestSpanEnd(
 
   onRequestSpanEnd?.(span, {
     headers: handlerData.response?.headers,
+    error: handlerData.error,
   });
 }