[CH] fallback for unsupported regex in re2

### Backend

CH (ClickHouse)

### Bug description

OptimizedRegularExpression: cannot compile re2: d(?!d), error: invalid perl operator: (?!. Look at https://github.com/google/re2/wiki/Syntax for reference.

### Spark version

None

### Spark configurations

_No response_

### System information

_No response_

### Relevant logs

_No response_

Start at the OptimizedRegularExpression path and compare the failing d(?!d) pattern with the RE2 syntax reference linked in the issue. Determine the intended fallback for unsupported expressions and add regression coverage for this case; done means the pattern no longer fails solely because RE2 rejects the Perl operator.

Written by the indexing model from the issue text.