IELM: "Error running timer ‘jit-lock-stealth-fontify’: (wrong-type-argument stringp...) (same as #5187)

### I confirm that...

- [X] I have searched the [issue tracker](https://github.com/doomemacs/doomemacs/issues), [documentation](https://docs.doomemacs.org), [FAQ](https://docs.doomemacs.org/-/faq), [Discourse](https://discourse.doomemacs.org), and [Google](https://google.com), in case this issue has already been reported/resolved.

- [X] I have read "[How to Debug Issues](https://doomemacs.org/d/how2debug)", and will use it to provide as much information about this issue as possible.

- [X] The issue can be reproduced on the **latest** available commit of Doom.

- [X] The issue can be reproduced on a stable release of Emacs, such as 27 or 28. *(Doom does not support development builds like 29+ or any version ending in .50 or .9x)*

### Expected behavior

Expectation: use IELM as an elisp REPL without fontification errors.

### Current behavior

Note: this report is identical to the one in #5187. Unfortunately the fix did not resolve the issue for me and it persists on latest main branch and latest stable Emacs.

Note also that I can work around the issue via `(setq ielm-font-lock-keywords nil)`. However, if I don't do this, constant fontification errors persist:

```
Error running timer ‘jit-lock--debug-fontify’: (wrong-type-argument stringp #[257 "\30021\0\301\302�\303#\2050\0\304\224\204�\0\305`S\306\"\211<\203!\0\307�>\204'\0\211\307=\203,\0\310\300\303\"\210\210\202�\00\207" [found re-search-forward "\\(\\\\\\\\\\)\\(?:\\(\\\\\\\\\\)\\|\\((\\(?:\\?[0-9]*:\\)?\\|[|)]\\)\\)" t 2 get-text-property face font-lock-string-face throw] 5 "

(fn BOUND)"])
```

### Steps to reproduce

1. Open emacs
2. M-x ielm
3. M-x jit-lock-debug mode
4. Observe fontification error message

### System Information

https://pastebin.com/ApjzRHUB