[SPARK-3834][SQL] Backticks not correctly handled in subquery aliases

The queries like SELECT a.key FROM (SELECT key FROM src) \`a\` does not work as backticks in subquery aliases are not handled properly. This PR fixes that.

Author : ravipesala ravindra.pesalahuawei.com

Author: ravipesala <ravindra.pesala@huawei.com>

Closes #2737 from ravipesala/SPARK-3834 and squashes the following commits:

0e0ab98 [ravipesala] Fixing issue in backtick handling for subquery aliases