IBX-10955: Changed UDW z-index to cover help center btn (#1771)

Author: albozek

src/bundle/Resources/public/scss/_dropdown-popover.scss

@@ -1,5 +1,6 @@
 .ibexa-dropdown-popover {
     &.popover {
+        z-index: 10250;
         max-width: initial;
         background: initial;
         border: 0;

src/bundle/Resources/public/scss/_extra-actions.scss

@@ -144,6 +144,8 @@
     }
 
     &--create {
+        z-index: 10250;
+
         #{$self} {
             &__content {
                 max-height: calc(100% - #{calculateRem(155px)});

src/bundle/Resources/public/scss/ui/modules/universal-discovery/_main.scss

@@ -1,6 +1,6 @@
 .m-ud {
     position: fixed;
-    z-index: 2100;
+    z-index: 10250;
     top: 0;
     left: 0;
     height: 100vh;

src/bundle/Resources/public/scss/ui/modules/universal-discovery/_tab.scss

@@ -76,7 +76,7 @@
     &__dropdown-portal {
         .ibexa-dropdown__items {
             position: fixed;
-            z-index: 250;
+            z-index: 10250;
         }
     }
 }