[Fix](Nereids) fix append_trailing_char_if_absent function return null#40820

morrySnow merged 2 commits intoapache:masterapache/doris:masterfrom

LiBinfeng-01:fix_function_append_trailing_char_if_absentLiBinfeng-01/doris:fix_function_append_trailing_char_if_absentCopy head branch name to clipboard