Actually adjust copy button logic to new API

Remove the obsolete textarea creation and correctly handle other permission errors

Author: D3SOX

core/src/main/resources/lib/layout/copyButton/copyButton.js

@@ -7,28 +7,19 @@ Behaviour.specify(
       // HTMLUnit 2.70.0 does not recognize isSecureContext
       // https://issues.jenkins.io/browse/JENKINS-70895
       if (!window.isRunAsTest && isSecureContext) {
-        // Make an invisible textarea element containing the text
-        const fakeInput = document.createElement("textarea");
-        fakeInput.value = copyButton.getAttribute("text");
-        fakeInput.style.width = "1px";
-        fakeInput.style.height = "1px";
-        fakeInput.style.border = "none";
-        fakeInput.style.padding = "0px";
-        fakeInput.style.position = "absolute";
-        fakeInput.style.top = "-99999px";
-        fakeInput.style.left = "-99999px";
-        fakeInput.setAttribute("tabindex", "-1");
-        document.body.appendChild(fakeInput);
-
-        // Select the text and copy it to the clipboard
-        fakeInput.select();
-        navigator.clipboard.writeText(fakeInput.value);
-
-        // Remove the textarea element
-        document.body.removeChild(fakeInput);
-
-        // Show the completion message
-        hoverNotification(copyButton.getAttribute("message"), copyButton);
+        // Copy the text to the clipboard
+        navigator.clipboard
+          .writeText(copyButton.getAttribute("text"))
+          .then(() => {
+            // Show the completion message
+            hoverNotification(copyButton.getAttribute("message"), copyButton);
+          })
+          .catch(() => {
+            hoverNotification(
+              "Could not get permission to write to clipboard",
+              copyButton,
+            );
+          });
       } else {
         hoverNotification(
           "Copy is only supported with a secure (HTTPS) connection",