[Bug]: bash profile file leaks new_dirs into the environment in some situations

[leio]

Checklist

• I agree to follow the Code of Conduct that this project adheres to.
• I have searched the issue tracker for a bug that matches the one I want to file, without success.
• If this is an issue with a particular app, I have tried filing it in the appropriate issue tracker for the app (e.g. under https://github.com/flathub/) and determined that it is an issue with Flatpak itself.
• This issue is not a report of a security vulnerability (see here if you need to report a security issue).

Flatpak version

1.14.4

What Linux distribution are you using?

Gentoo Linux

Linux distribution version

No response

What architecture are you using?

aarch64

How to reproduce

su -
set |grep flatpak

outputs

XDG_DATA_DIRS=/root/.local/share/flatpak/exports/share:/var/lib/flatpak/exports/share:/usr/local/share:/usr/share:/usr/share/gdm
new_dirs=/root/.local/share/flatpak/exports/share:/var/lib/flatpak/exports/share

Expected Behavior

$new_dirs isn't in list of set variables in any situation.

I think running unset new_dirs at the end in profile/flatpak.sh should fix it, and it does for me, but I don't know the intricacies of this stuff, nor if it could be something to solve for other shell profile files as well.

Actual Behavior

new_dirs is exposed into the environment when the shell profiles are sourced in certain ways, e.g. via su -

Additional Information

No response