[Bug]: segfault when answering 'n' on flatpak install

[jakedane]

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

1.15.7

What Linux distribution are you using?

Arch Linux

Linux distribution version

rolling

What architecture are you using?

x86_64

How to reproduce

1. Install an app, for example Brave Browser, with command flatpak install com.brave.Browser
2. On the question Proceed with these changes to the system installation? [Y/n]: answer n to not proceed

Expected Behavior

flatpak command exits cleanly.

Actual Behavior

flatpak throws a segmentation fault.

Core was generated by `flatpak install com.brave.Browser'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x0000706910cf2d49 in g_type_check_instance_is_fundamentally_a (type_instance=0x63fd43502e1e, fundamental_type=80) at ../glib/gobject/gtype.c:4151
4151      if (!type_instance || !type_instance>g_class)  

Full backtrace with debug symbols:
gdb.txt

Additional Information

When I answer y the app installs fine so the segfault only happens when answering n.

[chrisawi]

Can confirm. Bisecting points to 6e3cc82