How to clear. Display error medsage

I don't think it can be removed at all. Your iPhone is designed to trigger this alert if a non-Apple part has been installed.

About genuine iPhone displays - Apple Support

Moving forward, it is best to bring your Apple devices at an Apple Store or Apple Authorized Service Provider for repair/service

You do have the option to let a technician inspect the phone.

Apple Repair and Repair Status Check - Official Apple Support

The unknown part error is as important as the Check Engine light in your car.

—It needs to be serviced A.S.A.P.—

Get expert service and support at the Genius Bar.

Click ▶︎ Start a Service Request. ⚛️

Need more help?

• Call Apple Support at 1-800-APLCARE. 📞
• International Support. 🌐
• Contact Apple Support. 📝
• Chat using Messages. 💬

Click ▶︎ Check Repair Status.