fix(CodeModal): Adjust PF code editor header border

PatternFly looks like it changed the way the border is applied in pre-release version. The spacing of the tabs were also changed. Adjusting our styles to account for change.

Author: rebeccaalpert

packages/module/src/CodeModal/CodeModal.scss

@@ -7,6 +7,7 @@
     --pf-v6-c-code-editor--m-read-only__main--BackgroundColor: #1f1f1f;
   }
   .pf-v6-c-code-editor__header {
+    --pf-v6-c-code-editor__header--BorderWidth: 0;
     background: #1f1f1f !important;
     /** this is for the attachment editor header */
     border-start-start-radius: var(--pf-t--global--border--radius--small);