fix: actually clear pending requests in DevToolsAgentHost (#27440)

Co-authored-by: Shelley Vohr <shelley.vohr@gmail.com>

shell/browser/api/electron_api_debugger.cc

@@ -185,6 +185,7 @@ v8::Local<v8::Promise> Debugger::SendCommand(gin::Arguments* args) {
 void Debugger::ClearPendingRequests() {
   for (auto& it : pending_requests_)
     it.second.RejectWithErrorMessage("target closed while handling command");
+  pending_requests_.clear();
 }
 
 // static