"Flashing Completed" UI is confusing when errors occur

[j-tai]

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

NAME="Pop!_OS"
VERSION="20.10"
ID=pop
ID_LIKE="ubuntu debian"
PRETTY_NAME="Pop!_OS 20.10"
VERSION_ID="20.10"
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=groovy
UBUNTU_CODENAME=groovy
LOGO=distributor-logo-pop-os

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

popsicle-gtk:
  Installed: 1.3.0~1609365419~20.10~5a49bee
  Candidate: 1.3.0~1609365419~20.10~5a49bee
  Version table:
 *** 1.3.0~1609365419~20.10~5a49bee 1001
       1001 http://ppa.launchpad.net/system76/pop/ubuntu groovy/main amd64 Packages
        100 /var/lib/dpkg/status

Issue/Bug Description:

The "Flashing Completed" screen is displayed even when an error occurs during flashing. The big green check mark and "Flashing Completed" heading are confusing, as it can lead the user to think that flashing succeeded when it did not.

Steps to reproduce (if you know):

1. Flash any image onto any USB stick
2. Unplug the USB stick during flashing to trigger an I/O error

Expected behavior:

If an error occurs during flashing, the screen should not have a bright green check mark with the text "Flashing Completed." Perhaps it could say "Flashing Failed," "Error during Flashing," or "Flashing Completed with Errors", and the check mark could be replaced with an X, a warning symbol, or similar.