fix(editor): Only show previews if the param is an expression (#14720)

Co-authored-by: Elias Meire <elias@meire.dev>

packages/frontend/editor-ui/src/components/AssignmentCollection/Assignment.test.ts

@@ -62,4 +62,11 @@ describe('Assignment.vue', () => {
 
 		expect(emitted('remove')).toEqual([[]]);
 	});
+
+	it('should not display parameter input hint if expressionOutput is not set', () => {
+		const { getByTestId } = renderComponent();
+
+		// Check if the parameter input hint is not displayed
+		expect(() => getByTestId('parameter-input-hint')).toThrow();
+	});
 });