Fix(Dialog): set height limit of 35% to DialogHeader (#5996)

Co-authored-by: Copilot <[email protected]>

Author: francinelucca

.changeset/tame-pumpkins-jump.md

@@ -0,0 +1,5 @@
+---
+"@primer/react": patch
+---
+
+Fix(Dialog): set height limit of 35% to DialogHeader

packages/react/src/Dialog/Dialog.module.css

@@ -214,7 +214,9 @@
 
 .Header {
   z-index: 1;
+  max-height: 35vh;
   padding: var(--base-size-8);
+  overflow-y: auto;
   /* stylelint-disable-next-line primer/box-shadow */
   box-shadow: 0 1px 0 var(--borderColor-default);
   flex-shrink: 0;