Revert "Don't cripple the icu data"

This reverts commit 9b60017d, which
caused build failures

[build PAT] icu_data
/bin/sh: line 0: cd: C:/lo/core/workdir/wntmsci13.pro/UnpackedTarball/icu_data: No such file or directory

presumably because icu/UnpackedTarball_icu.mk explicitly references
$(call gb_UnpackedTarball_get_target,icu_data).

icu/Module_icu.mk

@@ -12,6 +12,7 @@ $(eval $(call gb_Module_Module,icu))
 ifeq ($(SYSTEM_ICU),NO)
 $(eval $(call gb_Module_add_targets,icu,\
 	UnpackedTarball_icu \
+	UnpackedTarball_icu_data \
 	ExternalPackage_icu \
 	ExternalProject_icu \
 ))