Fix SIMILAR TO percent wildcard

[akmhatey-ai]

Closes #22263.

Summary

• translate SIMILAR TO pattern operands before the existing regex-match evaluation
• map SQL wildcards % to .* and _ to . for scalar and array pattern expressions
• add coverage for SELECT 'abc' SIMILAR TO 'a%';

Validation

• cargo fmt --all --check
• cargo clippy -p datafusion-physical-expr --all-targets --all-features -- -D warnings
• cargo test -p datafusion-physical-expr expressions::binary::tests::test_similar_to --lib
• cargo test -p datafusion-sqllogictest --test sqllogictests -- strings:86
• git diff --check
• git diff --cached --check
• git diff --cached | gitleaks detect --pipe --redact --verbose --no-color

Full workspace test suite was not run locally.

Disclosure: I used AI-assisted tooling while preparing this patch.