fix(ObjectPage): increase header z-index

partial cherry-pick of #6116

Author: MarcusNotheis

packages/main/src/components/ObjectPage/ObjectPage.module.css

@@ -39,7 +39,7 @@
   background-color: var(--sapObjectHeader_Background);
   position: sticky;
   inset-block-start: 0;
-  z-index: 2;
+  z-index: 4;
   cursor: pointer;
   display: grid;
 
@@ -94,12 +94,12 @@
 
 .anchorBar {
   position: sticky;
-  z-index: 2;
+  z-index: 4;
 }
 
 .tabContainer {
   position: sticky;
-  z-index: 1;
+  z-index: 3;
 }
 
 .tabContainerComponent {