UI: Copy Filters menu is active only if applicable

UI/window-basic-main.cpp

@@ -5075,7 +5075,8 @@ void OBSBasic::CreateSourcePopupMenu(int idx, bool preview)
 		popup.addAction(QTStr("Properties"), this,
 				SLOT(on_actionSourceProperties_triggered()));
 
-		ui->actionCopyFilters->setEnabled(true);
+		ui->actionCopyFilters->setEnabled(
+			obs_source_filter_count(source) > 0);
 		ui->actionCopySource->setEnabled(true);
 	}
 	ui->actionPasteFilters->setEnabled(copyFiltersString && idx != -1);