Move screen invalid unicode prop text

`mini-vimrc.vim`:

```vim
set nowrap
```

Vim version: 9.1.2077

Reproduction steps:

1. Run `Vim -Nu mini-vimrc.vim`
2. Input `100Ix` `<esc>`
3. Input `:echo prop_type_add("foo", {}) | echo prop_add(1, 1, #{text:repeat("…", 70),type:"foo"})` `<cr>`
4. Input `100Iy` `<esc>`
5. Input `0150zl`

On first line first column, `…` displayed to `�` (U+FFFD)
