Ensure that the file tree takes up the full panel height (#17019)

GitOrigin-RevId: 9d4b63083c85dab946944c5f4f58f46340dd5056

services/web/frontend/stylesheets/app/editor/file-tree.less

@@ -17,8 +17,7 @@
 .file-tree {
   display: flex !important; // To work around jQuery layout's inline styles
   flex-direction: column;
-  flex-grow: 1;
-  max-height: 100%;
+  height: 100%;
 
   .toolbar.toolbar-filetree {
     .toolbar-small-mixin;