More reliable field length validation for multi-line text fields (38484457)

Field length validation for multi-line text fields has been enhanced to correctly handle text containing line breaks and multi-byte characters, such as emojis. When entered text exceeds the maximum allowed length, it is now truncated appropriately to fit the field size. Previously, certain content could cause the client-side validation to calculate field length incorrectly, resulting in inconsistent validation or unexpected truncation.