fix(CopyButton): ensure copy text is placed over icons (#7611)

* fix(CopyButton): ensure copy text is placed over icons

* fix(CodeSnippet): fix tooltip positioning with multiple codesnippets

* fix(CodeSnippet): only set z-index on multi snippet

Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>

Author: tw15egan

packages/components/src/components/code-snippet/_code-snippet.scss

@@ -333,7 +333,6 @@
     position: absolute;
     top: 0;
     right: 0;
-    z-index: 10;
 
     // Override inherited rule in code snippet
     @include carbon--font-family('sans');
@@ -465,6 +464,7 @@
   .#{$prefix}--snippet--multi .#{$prefix}--copy-btn {
     top: $carbon--spacing-03;
     right: $carbon--spacing-03;
+    z-index: 10;
     width: $carbon--spacing-07;
     height: $carbon--spacing-07;
   }

packages/components/src/components/copy-button/_copy-button.scss

@@ -107,6 +107,7 @@
     .#{$prefix}--copy-btn__feedback {
       @include tooltip--content('icon');
 
+      z-index: 3;
       display: none;
       box-sizing: content-box;
       margin: auto;