[arborist] [Fix] build-ideal-tree: ensure indentation is preserved

Author: ljharb

workspaces/arborist/lib/arborist/build-ideal-tree.js

@@ -333,6 +333,8 @@ module.exports = cls => class IdealTreeBuilder extends cls {
             root.meta.lockfileVersion = defaultLockfileVersion
           }
         }
+        // ensure indentation is inferred properly
+        root.meta.indent = root.package[Symbol.for('indent')]
         return root
       })