Add libdumpstateutil to vendor variant list

This change adds libdumpstateutil to VndkMustUseVendorVariantList. This
is done to avoid a VNDK re-spin on aosp/2679475 and aosp/2681060, which
add the dumpstate util function IsStrictRun and make it framework-only.

Test: Presubmit; verify that builds still work on internal (refer to
      aosp/2681060 test).
Bug: 283326935
Change-Id: I3c60dd919a65182937d6e0b233635ff6ca9414d3