Update to FCS 43.8.100-preview.23478.1 #1858

Job	Run time
Build on windows-latest for repo global.json	18m 47s
Build on windows-latest for 6.0 stable	18m 35s
Build on windows-latest for 7.0 preview	19m 1s
Build on macos-latest for repo global.json	18m 34s
Build on macos-latest for 6.0 stable	23m 9s
Build on macos-latest for 7.0 preview	26m 32s
Build on ubuntu-latest for repo global.json	13m 31s
Build on ubuntu-latest for 6.0 stable	14m 14s
Build on ubuntu-latest for 7.0 preview	14m 19s
	2h 46m 42s

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