fix: Fixed wrong shift size for folders, b=no-bug, c=folders

Author: mr-cheffy

src/zen/folders/zen-folders.css

@@ -154,11 +154,11 @@ tab-group[split-view-group] .tabbrowser-tab {
 
 tab-group[split-view-group] .tab-group-label-container {
   position: absolute;
-  width: 100%;
-  height: 40px;
+  width: -moz-available;
+  height: 36px;
   visibility: hidden;
   padding: 0 !important;
-  margin: 0 !important;
+  margin: 2px 0 0 0 !important;
 }
 
 tab-group[split-view-group] .tab-close-button {
@@ -321,6 +321,8 @@ zen-folder {
       font-weight: 600;
       align-self: center !important;
       text-align: start;
+      align-content: center;
+      height: 100% !important;
 
       :root:not([zen-sidebar-expanded]) & {
         padding: 0 !important;