The "path": "/usr/bin/flatpak-spawn" settings trick not working

Attempting to use the host shell in the integrated terminal, and the `"path": "/usr/bin/flatpak-spawn"` trick in `settings.json` is not working for me. Interestingly, however, launching commands in the integrated terminal using the `flatpak-spawn --host` prefix works just fine(!). (Also, I checked, and my distro does _not_ have a `/usr/bin/flatpak-spawn` file, nor does there seem to be a `flatpak-spawn` file anywhere on my HDD.)

Here's what the terminal says:
```
sh-5.1$ flatpak-spawn --host swupd search java
[270 preload-host-spawn-strategy] Warning: waitpid override ignores groups
Bundle with the best search result:
java-basic - Build and run Java language programs. (506MB)

This bundle can be installed with:

swupd bundle-add java-basic

Alternative bundle options are
java11-basic - Build and run Java 11 language programs. (310MB)
java13-basic - Build and run Java 13 language programs. (330MB)
nodejs-basic - Run JavaScript server side for fast, scalable network applications. (300MB)
[270 preload-host-spawn-strategy] Warning: waitpid override ignores groups
sh-5.1$ swupd search java
[270 preload-host-spawn-strategy] Warning: waitpid override ignores groups
sh: swupd: command not found
[270 preload-host-spawn-strategy] Warning: waitpid override ignores groups
sh-5.1$
```
What am I doing wrong?

(My distro is Clear Linux.)

Start by reproducing the integrated-terminal behavior on Clear Linux using the settings.json path and the working flatpak-spawn --host command shown in the report. Trace how the configured terminal path is resolved, then identify and document the cause or required configuration; done means the configured path works or the limitation is clearly explained.

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