feat: add apply for presets

src/main.py

@@ -601,6 +601,9 @@ class GradienceApplication(Adw.Application):
                         os.path.join(gtk3_dir, "gtk.css"), "w", encoding="utf-8"
                     ) as file:
                         file.write(gtk3_css)
+            
+            self.plugins_list.apply()
+                
             self.win.toast_overlay.add_toast(
                 Adw.Toast(title=_("Preset set sucessfully"))
             )

src/plugins_list.py

@@ -92,3 +92,7 @@ class GradiencePluginsList:
             if error:
                 errors.append(detail)
         return errors
+
+    def apply(self):
+        for pluginInfo in self.pm.getAllPlugins():
+            pluginInfo.plugin_object.apply()