webhook current URL being used multiple times by edit

When trying to create a webhook of the same URL it will throw an error. Since we don’t allow the same URL to be registered. but if a user creates one webhook with URL-a and another second webhook with URL-b . then later the user can edit the URL of second webhook to be URL-a (which is not correct) and as a result we will have two webhook with the same URL.

Below attached images shows the issue.

Below same URL two webhooks. (after user creates and edits the URL to have the same URL)