ci: Upgrade Fedora jobs to versions 40 and 41

As discussed in #1158 (closed), Fedora 37 is EOL since December 2023. This version has some bugs when compiling ns-3 that have been causing issues for some time.

This MR proposes to raise the minimum supported version of Fedora to 40 and 41, which are the currently supported versions.

Fix #1158 (closed)