Japanese input on macOS regressed in Qt 6.5.3

Reproduction steps:

• Open the markdown editor example
• Switch to Japanese keyboard input
• On the left, type 'taberu', then press down a few times. Notice how the text you input changes as you cursor down.
• In English, type <input> so you can enter something into webengine on the right.
• Enter taberu on the right and cursor down. Notice how the input text gets blanked out.