Generate product partition filesystem module in filesystem_creator

Bug: 374388294
Test: CI
Change-Id: I02786d0e9bf1a43a3527b647d5379d35e489076c
diff --git a/android/config.go b/android/config.go
index b70f6ac..686e861 100644
--- a/android/config.go
+++ b/android/config.go
@@ -1558,6 +1558,10 @@
 	return "product"
 }
 
+func (c *deviceConfig) BuildingProductImage() bool {
+	return proptools.Bool(c.config.productVariables.BuildingProductImage)
+}
+
 func (c *deviceConfig) SystemExtPath() string {
 	if c.config.productVariables.SystemExtPath != nil {
 		return *c.config.productVariables.SystemExtPath