fix: ensure ElectronBrowser mojo service is only bound to appropriate render frames (#33323)

* fix: ensure ElectronBrowser mojo service is only bound to authorized render frames

Notes: no-notes

* refactor: extract electron API IPC to its own mojo interface

* fix: just check main frame not primary main frame

shell/common/gin_helper/event_emitter.h

@@ -29,7 +29,7 @@ v8::Local<v8::Object> CreateNativeEvent(
     v8::Isolate* isolate,
     v8::Local<v8::Object> sender,
     content::RenderFrameHost* frame,
-    electron::mojom::ElectronBrowser::MessageSyncCallback callback);
+    electron::mojom::ElectronApiIPC::MessageSyncCallback callback);
 
 }  // namespace internal