Duplicate Element When Pressing Enter While Composing

[lamtuanamc]

Summary: When typing in Vietnamese in a command (e.g., /file, /image, /video, /table), if there are still underlined words (indicating that they are in the process of being composed), pressing Enter results in the duplication of the element. However, clicking the button on the menu does not cause this issue.

Steps to Reproduce:

1. Start typing a command such as /file, /image, /video, or /table in Vietnamese.
2. Ensure that there are still underlined words (indicating that the words are being composed).
3. Press Enter to submit the command.

https://github.com/TypeCellOS/BlockNote/assets/37234239/e449b36a-f2ae-4114-88d3-9ecbba462c48