Add the missing rule for including product_services.img into vbmeta.img.

Bug: 80741439
Test: `m -j vbmetaimage` for a target that uses product_services image
      (i.e. `BOARD_PRODUCT_SERVICESIMAGE_FILE_SYSTEM_TYPE := ext4`).
      Verify that the generated `vbmeta.img` includes the descriptor for
      `product_services.img`.
Change-Id: Ia2d64523319c3313803acbc63dd56154a0426334