Details window uses double spacing of characters (characters seem to have double wide bounding boxes) impairing readability

Reproduce the issue by opening the Details window after an update action, then compare its text with the View => Information log on Linux Mint 22.3 Xfce using mintupdate 7.1.4. Trace the UI entry point for the Details dialog and its log display. Done means both views render characters with normal single spacing without impairing readability.

Describe the bug
A clear and concise description of what the bug is.

Screenshots

Steps to reproduce

1. Wait for update to be available, or choose some item to remove, and proceed
2. Click "Details" button once shown
3. Observe that c h a r a c t e r s a r e d o u b l e - s p a c e d
4. Once finished, check the log under View => Information and see that characters showing d a t e a n d t i m e are also double-spaced. By marking one character you can see that the extra spacing is caused by wider bounding box, not an added space.

Expected behaviour
Characters should be single-spaced because double-spacing makes them hard to read.

Distribution:
Linux Mint 22.3 Xfce

Software version:
mintupdate 7.1.4

Logs:
2026.09.04@16:25 ++ Launching Update Manager
2026.09.04@16:25 ++ Initial refresh will happen in 0 day(s), 0 hour(s) and 10 minute(s)
2026.09.04@16:25 ++ Inhibited power management
2026.09.04@16:25 ++ Checking for updates
2026.09.04@16:25 ++ System is up to date
2026.09.04@16:25 ++ Refresh finished
2026.09.04@16:25 ++ Resumed power management

vs. screenshot:

Additional context
I thought perhaps it is a font issue, but this does not appear to be the system default monospace font, so I can't seem to be able to change it. The equivalent dialog in Synaptic does not show double spaces, but it uses a different font so perhaps it's unrelated.

Locale:
If the problem is with text not getting displayed correctly, paste the output of the terminal command locale.
LANG=en_CA.UTF-8
LANGUAGE=en_CA:en
LC_CTYPE="en_CA.UTF-8"
LC_NUMERIC="en_CA.UTF-8"
LC_TIME="en_CA.UTF-8"
LC_COLLATE="en_CA.UTF-8"
LC_MONETARY="en_CA.UTF-8"
LC_MESSAGES="en_CA.UTF-8"
LC_PAPER="en_CA.UTF-8"
LC_NAME="en_CA.UTF-8"
LC_ADDRESS="en_CA.UTF-8"
LC_TELEPHONE="en_CA.UTF-8"
LC_MEASUREMENT="en_CA.UTF-8"
LC_IDENTIFICATION="en_CA.UTF-8"
LC_ALL=