aux/indices: include provoking vertex check in prim type conversion

aux/indices: include provoking vertex check in prim type conversion

Include provoking vertex checking in u_index_prim_type_convert() to make sure
the right primitive type is returned from the generator function.

Fixes google earth running on VMware svga device on hw version 11.

Fixes: cad2026b72cf ("aux/indices: break out primitive type conversion to separate function")

Reviewed-by: Charmaine Lee <charmainel@vmware.com>
Reviewed-By: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11367>