Back button doesn't work

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

NAME="Pop!_OS"
VERSION="21.10"
ID=pop
ID_LIKE="ubuntu debian"
PRETTY_NAME="Pop!_OS 21.10"
VERSION_ID="21.10"
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=impish
UBUNTU_CODENAME=impish
LOGO=distributor-logo-pop-os

Related Application and/or Package Version (run apt policy $PACKAGE NAME):

pop-installer:
  Installed: 0.0.1~1639146907~21.10~4ba72f9
  Candidate: 0.0.1~1639146907~21.10~4ba72f9
  Version table:
 *** 0.0.1~1639146907~21.10~4ba72f9 1001
       1001 http://apt.pop-os.org/release impish/main amd64 Packages
        100 /var/lib/dpkg/status

Issue/Bug Description: The back button in the custom page doesn't work

Steps to reproduce (if you know): Go into the partitionView and click back. It doesn't work.

Expected behavior: Either take the user back a view, or just remove it, because there is a Cancel Install button right next to it. Which takes the user to the same place.

Other Notes:

https://user-images.githubusercontent.com/58987761/146619868-20cb742b-3855-47a5-8f77-ef549a60514d.mp4

pop-os / installer

Back button doesn't work #253