Unit Controls widget title does not use the configured font size

[jwrober]

Describe the bug
The Unit Controls widget's title bar font is statically assigned and doesn't follow the notify font size in the interface options

Expected behavior
You can set the font you want.

Screenshots
N/A

Platform and version (please complete the following information):

• OS: yes, all of them
• Freeciv21 version: 3.1-beta.1]
• Ruleset/Longturn game (if applicable): N/A

Additional context
Came up as part of a Discord conversation
https://discord.com/channels/378908274113904641/379424175623766027/1282624251328856157

[lmoureaux]

The font name and style are used, but the size is modified by the widget.