Rename product_services to system_ext

Bug: 134359158
Test: build and check if system_ext.img is created
Change-Id: I67f2e95dd29eac6a28e07e24ea973d3a134c3bfc
diff --git a/core/dex_preopt_config.mk b/core/dex_preopt_config.mk
index 570dbd8..b856bf4 100644
--- a/core/dex_preopt_config.mk
+++ b/core/dex_preopt_config.mk
@@ -8,8 +8,8 @@
 SYSTEM_OTHER_ODEX_FILTER ?= \
     app/% \
     priv-app/% \
-    product_services/app/% \
-    product_services/priv-app/% \
+    system_ext/app/% \
+    system_ext/priv-app/% \
     product/app/% \
     product/priv-app/% \