Make fmq product_available

Vendors already can use these targets on /vendor. This change makes them
available to /product as well.

More about product partitions:
https://source.android.com/docs/core/architecture/partitions/product-partitions

Bug: 336989719
Test: mm
Change-Id: I2cb1817525d4b2b3033e0e633ea2f8e7f5653a6c