### Godot version

4.2.dev4

### System information

macOS 13.5.1

### Issue description

The recent addition of an option in iOS export templates to "Export project only" is a welcome addition, since I've always had to set up some final things in XCode anyway for the builds to work. 

![Screenshot 2023-09-06 at 10 35 58](https://github.com/godotengine/godot/assets/17763524/672816ec-253a-4c66-a256-f2b627d7f857)

However, a small issue is that even when it's enabled the export Save dialogue lists the file extension as .ipa as if it's still going to export an app archive and not just the xcode project as expected. 

### Steps to reproduce

- Create an iOS export template.
- Enable the "Export project only" option
- Click "Export project..."
- Observe that the export save dialogue still lists the format as ipa.

![Screenshot 2023-09-06 at 10 40 57](https://github.com/godotengine/godot/assets/17763524/fb6c4e25-ecfc-4619-a04b-504a743d1d9b)


### Minimal reproduction project

Not project related, general export UI.
bool dc = devices_changed.is_set();
		if (dc) {
			
			devices_changed.clear();
		}
		return dc;
	}
	virtual bool should_update_export_options() override {
		bool export_options_changed = plugins_changed.is_set();
		if (export_options_changed) {
			
			plugins_changed.clear();
		}
		return export_options_changed;
	}
	virtual List<String> get_binary_extensions(const Ref<EditorExportPreset> &p_preset) const override {
		List<String> list;
		list.push_back("ipa");
		return list;
	}
	virtual Error export_project(const Ref<EditorExportPreset> &p_preset, bool p_debug, const String &p_path, int p_flags = 0) override;
	virtual bool has_valid_export_configuration(const Ref<EditorExportPreset> &p_preset, String &r_error, bool &r_missing_templates, bool p_debug = false) const override;
	virtual bool has_valid_project_configuration(const Ref<EditorExportPreset> &p_preset, String &r_error) const override;
	virtual void get_platform_features(List<String> *r_features) const override {
		r_features->push_back("mobile");
		r_features->push_back("ios");
	}
	virtual void resolve_platform_feature_priorities(const Ref<EditorExportPreset> &p_preset, HashSet<String> &p_features) override {