Frontend.XF.*: fix references in .fsproj files #2788

Job	Run time
macOS--dotnet6-and-mono	20m 31s
macOS--dotnet6-only	5m 19s
linux-github--dotnet-and-mono	4m 36s
linux-github--dotnet-and-newmono	7m 17s
linux-vanilla--newmono-only	9m 46s
linux-vanilla--stockdotnet6-and-newmono	7m 14s
linux-vanilla--stockdotnet6-and-stockmono	8m 58s
linux-vanilla--stockdotnet6-only	5m 29s
linux-vanilla--stockmono-only	5m 58s
macOS--mono-only	18m 48s
windows--dotnet6-and-legacyFramework	8m 51s
windows--dotnet6-only	8m 52s
windows--legacyFramework-only	13m 24s
conventions	1m 27s
snap_pkg	10m 56s
	2h 17m 26s

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