ESQL: pushdown to_upper/to_lower in like/rlike #127479
Description
Description
Similar to #118304, ESQL should catch this "pattern" not just for equality but also pattern matching:
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| WHERE TO_UPPER(string_a) like "String" // this will never match since the value contains lower case chars
| WHERE TO_LOWER(string_b) like "abc" // rewritten as a case-insensitive wildcard query
| WHERE TO_LOWER(string_b) rlike "abc.*xyz" // rewritten as a case-insensitive regex query
...