Fix webchannel wrapper overrides (firebase#7593)

* Fix webchannel wrapper overrides

* Create fresh-frogs-heal.md

* Update fresh-frogs-heal.md

* Update fresh-frogs-heal.md

Author: wu-hui

.changeset/fresh-frogs-heal.md

@@ -0,0 +1,6 @@
+---
+"@firebase/firestore": patch
+"@firebase/webchannel-wrapper": patch
+---
+
+Fix an issue where Firestore was incorrectly using XHR instead of fetch for streaming response.

packages/webchannel-wrapper/externs/overrides.js

@@ -66,6 +66,9 @@ goog.net.WebChannel.Options.forceLongPolling;
 /** @type {boolean|undefined} */
 goog.net.WebChannel.Options.detectBufferingProxy;
 
+/** @type {boolean|undefined} */
+goog.net.WebChannel.Options.useFetchStreams;
+
 /** @type {unknown} */
 goog.net.WebChannel.Options.xmlHttpFactory;