CI: add ubuntu24.04 vanilla jobs #3603

Job	Run time
macOS--mono-only	6m 20s
macOS--dotnet6-only	7m 24s
macOS--dotnet6-and-mono	4m 48s
windows--dotnet6-and-legacyFramework	5m 46s
linux20-github--dotnet-and-mono	3m 27s
linux20-vanilla--newmono-only	5m 47s
linux20-vanilla--stockmono-only	4m 50s
linux20-github--dotnet-and-newmono	3m 24s
linux22-github--dotnet-and-newmono	3m 37s
linux22-github--dotnet-and-mono	3m 41s
linux22-vanilla--newmono-only	5m 39s
linux22-vanilla--stockdotnet6-and-newmono	9m 0s
linux22-vanilla--stockdotnet6-and-stockmono	4m 48s
linux22-vanilla--stockdotnet6-only	4m 41s
linux22-vanilla--stockmono-only	4m 57s
linux24-vanilla--newmono-only	5m 42s
linux24-vanilla--stockdotnet8-and-newmono	2m 4s
linux24-vanilla--stockdotnet8-and-stockmono	1m 22s
linux24-vanilla--stockmono-only	4m 45s
linux24-vanilla--stockdotnet8-only	1m 17s
windows--dotnet6-only	6m 37s
windows--legacyFramework-only	13m 20s
conventions	1m 18s
snap_pkg	3m 55s
	1h 58m 29s

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