Installation over existing filesystem with whitespace in name fails

[curiousercreative]

Distribution (run cat /etc/os-release):

$ cat /etc/os-release
NAME="Pop!_OS"
VERSION="22.04 LTS"
ID=pop
ID_LIKE="ubuntu debian"
PRETTY_NAME="Pop!_OS 22.04 LTS"
VERSION_ID="22.04"
HOME_URL="https://pop.system76.com"
SUPPORT_URL="https://support.system76.com"
BUG_REPORT_URL="https://github.com/pop-os/pop/issues"
PRIVACY_POLICY_URL="https://system76.com/privacy"
VERSION_CODENAME=jammy
UBUNTU_CODENAME=jammy
LOGO=distributor-logo-pop-os

Steps to reproduce (if you know):

1. Format a thumb drive or other removable media with an ext4 filesystem with whitespace in the name (ie "pop backup").
2. Go through installer, clean install for the device from step 1

Expected behavior:
Installation should proceed as normal,

Other Notes:
I don't have a copy of the installer log, but I recall seeing the error being related to an attempt to unmount the existing file system (despite it not being mounted) and returning an OS, file not found or something similar. Seems like the mount path isn't being escaped for white space.

[curiousercreative]

I'm pretty certain this is the same issue as #326