Only set Newt window icons on Windows (#1398) #671

Job	Run time
Test Processing	3m 4s
(linux/x64) Create Processing Build	9m 58s
(macos/x64) Create Processing Build	18m 14s
(windows/x64) Create Processing Build	8m 10s
(macos/aarch64) Create Processing Build	5m 54s
(linux/aarch64) Create Processing Build	8m 15s
	53m 35s

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