Make libavservices_minijail vendor_available

As we described "libavservices_minijail" in Andorid.bp, we don't need
to keep "libavservices_minijail_vendor" as a workaround, but may make
"libavservices_minijail" vendor_available and remove
"libavservices_minijail_vendor".

We will keep "libavservices_minijail_vendor" until we replace
"libavservices_minijail_vendor" to "libavservices_minijail" from all
vendor modules.

"libavservices_minijail_vendor" will be removed once the vendor
modules are cleaned up.

Bug: 146313710
Bug: 145580164
Test: build and boot
Change-Id: Iffb16c10ddc93e645d5839ac8aa320353e46d224