Cannot install event loop hook for "qt6" when running with `--simple-prompt` (ipython-8.20.0) but ipython-8.14.0 OK

With ipython-8.20.0 I get:
```
ipython3.12 --simple-prompt
Python 3.12.1 (main, Dec 18 2023, 00:00:00) [GCC 13.2.1 20231011 (Red Hat 13.2.1-4)]
Type 'copyright', 'credits' or 'license' for more information
IPython 8.20.0 -- An enhanced Interactive Python. Type '?' for help.

In [1]: %gui qt6
Cannot install event loop hook for "qt6" when running with `--simple-prompt`.
NOTE: Tk is supported natively; use Tk apps and Tk backends with `--simple-prompt`.
```

But if Ipython-8.14.0 this works
```
ipython --simple-prompt
Python 3.12.1 (main, Dec 18 2023, 00:00:00) [GCC 13.2.1 20231205 (Red Hat 13.2.1-6)]
Type 'copyright', 'credits' or 'license' for more information
IPython 8.14.0 -- An enhanced Interactive Python. Type '?' for help.

In [1]: %gui qt6
Installed qt6 event loop hook.
```

Since running ipython as subprocess under emacs require --simple-prompt, this is a problem for that environment.