CI: add ubuntu24.04 vanilla jobs #3602

Job	Run time
macOS--dotnet6-and-mono	9m 31s
macOS--mono-only	6m 34s
linux24-vanilla--stockdotnet8-only	1m 5s
linux24-vanilla--stockmono-only	4m 50s
macOS--dotnet6-only	6m 26s
windows--dotnet6-and-legacyFramework	5m 35s
windows--dotnet6-only	5m 28s
windows--legacyFramework-only	13m 0s
linux22-github--dotnet-and-mono	4m 0s
linux22-github--dotnet-and-newmono	3m 34s
linux22-vanilla--newmono-only	5m 39s
linux22-vanilla--stockdotnet6-and-newmono	5m 41s
linux22-vanilla--stockdotnet6-and-stockmono	4m 44s
linux22-vanilla--stockdotnet6-only	6m 34s
linux22-vanilla--stockmono-only	5m 14s
linux24-vanilla--newmono-only	6m 8s
linux24-vanilla--stockdotnet8-and-newmono	2m 9s
linux24-vanilla--stockdotnet8-and-stockmono	1m 13s
linux20-github--dotnet-and-mono	3m 22s
linux20-github--dotnet-and-newmono	3m 31s
linux20-vanilla--newmono-only	5m 27s
linux20-vanilla--stockmono-only	5m 16s
conventions	4m 23s
snap_pkg	0s
	1h 59m 24s

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