misc: enable `allWarningsAsErrors` #4257

Job	Run time
jvm (8)	5m 27s
jvm (21)	5m 28s
protocol-tests	10m 46s
jvm (11)	5m 25s
all-platforms (macos-latest)	5m 41s
all-platforms (windows-latest)	11m 18s
downstream	10m 24s
all-platforms (ubuntu-latest)	10m 15s
jvm (17)	5m 16s
	1h 10m 0s

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