Qt Quick Local Storage: (JS) null (passed as bound parameter) to executeSql() converts to empty string instead of NULL

When calling executeSql() which includes arguments marked with ?, passing null to that argument converts to empty string instead of being NULL in database.

Steps to reproduce:

• Run attached sample
• EXPECTED: Two entries are created in database, with second string being NULL for both entries
• ACTUAL: Two entries are created, with second string of first entry being empty string