[feature](function) support ngram_search function #38226 (#40893)
https://github.com/apache/doris/pull/38226
mysql [test]>select ngram_search('123456789' , '12345' , 3);
+---------------------------------------+
| ngram_search('123456789', '12345', 3) |
+---------------------------------------+
| 0.6 |
+---------------------------------------+
1 row in set (0.01 sec)
mysql [test]>select ngram_search("abababab","babababa",2);
+-----------------------------------------+
| ngram_search('abababab', 'babababa', 2) |
+-----------------------------------------+
| 1 |
+-----------------------------------------+
1 row in set (0.01 sec)
```
doc https://github.com/apache/doris-website/pull/899
## Proposed changes
Issue Number: close #xxx
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