How to delete an iMessage on MacBook Air without opening the text/clicking on it. M1, 2020

I have recevied a spam text from a gmail account and deleted it on my iphone without opening it. 

The message remains "unread" on my computer in iMessages. Like many I have had difficulties with Malware and do not want to open or click on the text & expose my computer. 

How can I delete this text on my MacBookAir without clicking on the text message? The system seems to have us click on the message in order to "Report Junk" but I need to Report Junk/Delete the text without opening the text.

Actions taken:

+ Created the spam email address a contact & have blocked the contact.

+ Restarted the phone and the computer.

+ All other text messages automatically sync between computer and iPhone.

+ Synced the phone & MBA.

+ Messages>Preferences>@messages>Settings and clicked "Sync Now"

Thank you!

MacBook Air, M1, 2020. Big Sur 11.4.

[Image Edited by Moderator to Remove Personal Information]