Throw error on requests like `"*"` in `FullText::Contains`

[stebloev]

[stebloev]

It should not only work for * pattern but for all patterns like ***. The meaning of pattern is the same but logic to detect such patterns becomes more complex

[stebloev]

For now we decided to explicitly decline support for such queries, because they are not leveraging fulltext index.

[stebloev]

This case also includes patterns like "ab*" when filter_ngram_min_length > 2.

In cases covered by this issue search terms are empty and that would be condition to throw error.

ydb/ydb/core/kqp/runtime/kqp_full_text_source.cpp

Line 1797 in 8e5949d

if (Words.empty()) {