[vts-core] add copy rules for *-gsi.avbpubkey

For using Gtest to run vts_security_avb_test and test it in the
vts-core, we have to add this rule to copy the *-gsi.avbpubkey to the
testcase folder.

Bug: 132702215
Test: 1. add data: "q-gsi.avbpubkey" to Android.bp of the module
      2. m module_name

Change-Id: I810231f39c970da4d2b8ab63daeee02379c7f952