[enhancement](array-type) Handle cast empty string value to array (#13028)
Handle empty value between two comma when cast string to array type.
before:
mysql> select cast("[a,b,c,,,,]" as array<string>);
+-----------------------------------+
| CAST('[a,b,c,,,,]' AS ARRAY<TEXT>) |
+-----------------------------------+
| ['a', 'b', 'c', ',', ','] |
+-----------------------------------+
1 row in set (0.01 sec)
after:
mysql> select cast("[a,b,c,,,,]" as array<string>);
+-----------------------------------+
| CAST('[a,b,c,,,,]' AS ARRAY<TEXT>) |
+-----------------------------------+
| ['a', 'b', 'c', '', '', ''] |
+-----------------------------------+
1 row in set (0.01 sec)
b8b18e5153