Restore Sass mixed-decls build check

Author: colinrotherham

shared/tasks/styles.mjs

@@ -55,7 +55,7 @@ export function compile(assetPath, { srcPath, destPath, output = {} }) {
           'color-functions',
           'global-builtin',
           'import',
-          // 'mixed-decls'
+          'mixed-decls'
         ],
         loadPaths: [join(paths.root, 'node_modules')],
         sourceMap: true,