lomiri: env is not entirely passed to apps
### Describe your issue
The entire environment is not passed to applications. This is most notably seen through the missing $HOME variable, causing apps to attempt to run with `/` as the home.
I am unsure if this is related, but it seems that `sudo` also does not get passed environment variables, but `sudo -i` still works.
(See https://gitlab.com/ubports/development/core/lomiri-app-launch/-/issues/18)
#### What's the expected behaviour?
Opening an app gives it the user's $PATH.
#### What's the current behaviour?
Opening an app gives it only partial portions of the user's $PATH
#### How to reproduce your issue?
Open any application. This is best seen through terminals, which cannot find a shell.
### What device are you using?
motorola-harpia (But this should affect all devices.)
### On what postmarketOS version did you encounter the issue?
* [x] edge (`feature/lomiri` branch)
* [ ] `v23.12`
* [ ] `v23.06`
* [x] I confirm that the issue still is present after running `sudo apk upgrade -a`
### On what environment did you encounter the issue?
#### Environments
* [ ] GNOME Shell on Mobile
* [ ] Phosh
* [ ] Plasma Mobile
* [ ] Sxmo (Wayland/Sway) **Please post the output of `sxmo_version.sh`**
* [x] Other: Lomiri
### How did you get postmarketOS image?
* [ ] from https://images.postmarketos.org
* [x] I built it using pmbootstrap
* [ ] It was preinstalled on my device
### Additional information
This is most likely an issue with `lomiri-app-launch`'s POSIX implementation not being as complex as the systemd implementation.
This also causes morph-browser to crash on startup with `Failed to create profile directory,unable to ensure a single instance of the application`.
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