flag_values: Enable AVF Custom VM support

* Makes it possible to run custom virtual machines. Refer to [1].
* Enable network too while at it (DICE and LLPVM are deps of network)

[1]: https://android.googlesource.com/platform/packages/modules/Virtualization/+/refs/tags/android-15.0.0_r3/docs/custom_vm.md

Change-Id: I5c677649edbf25b07076c3f857c9459df6becb87