Resolve "`Copy to Clipboard` tooltip appears under modal"

app/assets/stylesheets/framework/modal.scss

@@ -79,7 +79,6 @@ body.modal-open {
 
 .modal {
   background-color: $black-transparent;
-  z-index: 2100;
 
   @include media-breakpoint-up(md) {
     .modal-dialog {

app/assets/stylesheets/performance_bar.scss

@@ -6,7 +6,7 @@
   left: 0;
   top: 0;
   width: 100%;
-  z-index: 2000;
+  z-index: 1039;
 
   height: $performance-bar-height;
   background: $black;

changelogs/unreleased/41996-copy-to-clipboard-tooltip-appears-under-modal.yml

+---
+title: Solve tooltip appears under modal
+merge_request: 21017
+author:
+type: fixed