Fix the name of the channel parameter in PlatformMessage constructors (#9334)

Author: jason-simmons

lib/ui/window/platform_message.h

@@ -28,10 +28,10 @@ class PlatformMessage : public fml::RefCountedThreadSafe<PlatformMessage> {
   }
 
  private:
-  PlatformMessage(std::string name,
+  PlatformMessage(std::string channel,
                   std::vector<uint8_t> data,
                   fml::RefPtr<PlatformMessageResponse> response);
-  PlatformMessage(std::string name,
+  PlatformMessage(std::string channel,
                   fml::RefPtr<PlatformMessageResponse> response);
   ~PlatformMessage();