When the license is about to expired, there will be a message/warning/announcement appear on the top part of JIRA,it would be better if we have an option to disable the message permanently.

Workaround

Please note: This workaround will disable ALL global warnings for every user.

• Click on ⚙ > System > Announcement Banner and paste this code snippet into the box.

   <style type="text/css"> div.aui-message.aui-message-warning.warning {
       display: none;
  }
   </style>
  

• Choose the visibility level, then click on Set Banner.
• This should completely hide the license warning message along with any other warnings that may arise, therefore it is extremely important that you regularly perform health checks to see if there are any issues that you are not aware of if you choose to make use of this workaround.