fix(browser): Check for document when sending outcomes (#3993)

Author: AbhiPrasad

packages/browser/src/transports/base.ts

@@ -42,7 +42,7 @@ export abstract class BaseTransport implements Transport {
     // eslint-disable-next-line deprecation/deprecation
     this.url = this._api.getStoreEndpointWithUrlEncodedAuth();
 
-    if (this.options.sendClientReports) {
+    if (this.options.sendClientReports && document) {
       document.addEventListener('visibilitychange', () => {
         if (document.visibilityState === 'hidden') {
           this._flushOutcomes();