Replace PRODUCT_COPY_FILES with soong module

Include android.software.credentials.prebuilt.xml prebuilt_etc module
instead of using PRODUCT_COPY_FILES.

Bug: 345373198
Test: See if android.software.credentials.xml is installed in
      system/etc/permissions
Change-Id: Ia5519d1650b994f380aa4e31042139af999e49a7
diff --git a/target/product/generic_system.mk b/target/product/generic_system.mk
index 14efa67..0a09eb1 100644
--- a/target/product/generic_system.mk
+++ b/target/product/generic_system.mk
@@ -120,15 +120,15 @@
     init.zygote64.rc \
     init.zygote64_32.rc
 
+# Support Credential Manager
+PRODUCT_PACKAGES += \
+    android.software.credentials.prebuilt.xml
+
 # Enable dynamic partition size
 PRODUCT_USE_DYNAMIC_PARTITION_SIZE := true
 
 PRODUCT_ENFORCE_RRO_TARGETS := *
 
-# Support Credential Manager
-PRODUCT_COPY_FILES += \
-    frameworks/native/data/etc/android.software.credentials.xml:$(TARGET_COPY_OUT_SYSTEM)/etc/permissions/android.software.credentials.xml
-
 PRODUCT_NAME := generic_system
 PRODUCT_BRAND := generic