do not use subdomain

Author: mydea

dev-packages/browser-integration-tests/suites/errors/fetch/test.ts

@@ -39,9 +39,9 @@ sentryTest('handles fetch network errors on subdomains @firefox', async ({ getLo
   const eventData = envelopeRequestParser(await reqPromise);
 
   const errorMap: Record<string, string> = {
-    chromium: 'Failed to fetch (sentry-test-external.io)',
-    webkit: 'Load failed (sentry-test-external.io)',
-    firefox: 'NetworkError when attempting to fetch resource. (sentry-test-external.io)',
+    chromium: 'Failed to fetch (subdomain.sentry-test-external.io)',
+    webkit: 'Load failed (subdomain.sentry-test-external.io)',
+    firefox: 'NetworkError when attempting to fetch resource. (subdomain.sentry-test-external.io)',
   };
 
   const error = errorMap[browserName];

packages/core/src/utils-hoist/instrument/fetch.ts

@@ -120,10 +120,7 @@ function instrumentFetch(onFetchResolved?: (response: Response) => void, skipNat
           ) {
             try {
               const url = new URL(handlerData.fetchData.url);
-              // We only want to take the top-level domain, e.g. xxx.sentry.io should become sentry.io
-              // We do this to avoid noise when there may be dynamic subdomains
-              const host = url.host.split('.').slice(-2).join('.');
-              error.message = `${error.message} (${host})`;
+              error.message = `${error.message} (${url.host})`;
             } catch {
               // ignore it if errors happen here
             }