Regression in 0.74.1 (and 0.74.2) where there's an invalid space after the last character typed in Emacs, 0.74.0 works correctly

There's a regression in 0.74.1 (and 0.74.2) where there's an invalid space after the last character typed in Emacs. **fzf 0.74.0 works correctly in Emacs.**

Reproduction steps:

- Download https://github.com/bling/fzf.el/blob/master/fzf.el
- Download the fzf binaries

On Debian 13, using emacs 30.1

```
emacs -Q -l ~/Downloads/fzf.el '--eval=(setq fzf/executable "~/Downloads/fzf/fzf-0.74.1/deb13-64/fzf")'
```
(the -Q says don't load any customizations, the -l loads an elisp file, and the --eval sets the path to fzf)

Once in Emacs, type `M-x fzf` and you'll see something like the following where I typed the four characters `file`. After each character I type, there's an invalid space.

If I run 0.74.0, as I type I don't see the invalid space. For example, the last character I typed below was `e` in `file` and there's no invalid space.

```
emacs -Q -l ~/Downloads/fzf.el '--eval=(setq fzf/executable "~/Downloads/fzf/fzf-0.74.0/deb13-64/fzf")'
```

I've tried adding various options like `--no-unicode`, etc when using 0.74.1 and the problem persists.

fzf is used by many of us in Emacs and we greatly appreciate it. Thanks for creating and maintaining fzf.

Reproduce the issue with fzf.el under Emacs 30.1 using fzf 0.74.0 and 0.74.1, following the commands and typing M-x fzf. Compare the behavior and relevant changes between those fzf versions; done means the invalid trailing space no longer appears after typing characters in Emacs.

Written by the indexing model from the issue text.