[fix](json function) fix failed when json_exists_path use not null input #34289

[xiaokang]

cherry pick from #34289

[xiaokang]

run buildall

[doris-robot]

Thank you for your contribution to Apache Doris. Don't know what should be done next? See How to process your PR

Since 2024-03-18, the Document has been moved to doris-website. See Doris Document.

[xiaokang]

run p0

[xiaokang]

run buildall

[doris-robot]

TeamCity be ut coverage result: Function Coverage: 37.82% (8099/21417) Line Coverage: 29.46% (66118/224404) Region Coverage: 28.96% (34084/117691) Branch Coverage: 24.82% (17497/70508) Coverage Report: http://coverage.selectdb-in.cc/coverage/6612aec4ac1fd6f9a0f4534136e768486ced4220_6612aec4ac1fd6f9a0f4534136e768486ced4220/report/index.html