Embedded block is deleted after input a special Vietnamese character

[kido-luci]

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Flutter Quill Version

11.4.1

Steps to Reproduce

Set Up Environment:

• Use an iOS device or simulator.
• Focus a rich text input that supports embedded objects (e.g., a rich text editor with an embedded image or component).
• Ensure the Vietnamese Telex keyboard is enabled.

Insert Content:

• Add an embedded object (such as an image or block element).
• Immediately after the embedded object, type a Vietnamese word using Telex, e.g., dinh.

Trigger Word Transformation:

• Continue typing to trigger a transformation. For example, type an additional "d" to change "dinh" into đinh.

Observe Behavior:

• iOS deletes the word and re-inserts the transformed one.
• If the word is adjacent to the embedded object, iOS may also delete the \uFFFC character representing the embedded object.

Expected results

• Only the word should be updated, and the embedded object should remain intact.

Actual results

• The embedded object is unexpectedly removed or corrupted.
• The input state becomes inconsistent.

Bug Evidence