'Valid URI schemes' parameter affects already created URL widget

Steps to reproduce:

• Go to Dashboard and create URL Widget e.g:
  -) Name => TEST
  -) URL => https://zabbix.com
• Save Dashboard
• Got to Administration->General->Other
• Change Other configuration parameters:
  -) Valid URI schemes => dns
• Update changes
• Open Dashboard and check the previously created URL Widget

Result: URL is deleted, widget name is displayed as default "URL".

Expected: Correct widget name should be displayed and URL shouldn't be deleted.