### Godot version

v4.0.beta.custom_build [13f0158]

### System information

Windows 10

### Issue description

When doing operations (`begin_complex_operation` and `end_complex_operation`) with multiple selections in TextEdit, some of these selections don't revert upon undo. This behavior is affects some of script editor's operations, like duplicate selection and delete lines.

### Steps to reproduce

Open script editor, make multiple selections. Keep in mind what you have selected. Do duplicate selection (ctrl+shift+D). Undo (ctrl+Z). Compare the result to what you remember.

### Minimal reproduction project

N/A
ERR_FAIL_COND(p_op.type == TextOperation::TYPE_NONE);
	bool insert = p_op.type == TextOperation::TYPE_INSERT;
	if (p_reverse) {
		insert = !insert;
	}
	if (insert) {
		int check_line;
		int check_column;
		_base_insert_text(p_op.from_line, p_op.from_column, p_op.text, check_line, check_column);
		ERR_FAIL_COND(check_line != p_op.to_line); 
		ERR_FAIL_COND(check_column != p_op.to_column); 
	} else {
		_base_remove_text(p_op.from_line, p_op.from_column, p_op.to_line, p_op.to_column);
	}
}
void TextEdit::_clear_redo() {
	if (undo_stack_pos == nullptr) {
		return; 
	}
	_push_current_op();
	while (undo_stack_pos) {
		List<TextOperation>::Element *elem = undo_stack_pos;
		undo_stack_pos = undo_stack_pos->next();
		undo_stack.erase(elem);
	}
}
int TextEdit::_get_column_pos_of_word(const String &p_key, const String &p_search, uint32_t p_search_flags, int p_from_column) const {
	int col = -1;
	if (p_key.length() > 0 && p_search.length() > 0) {