Remove libvendorsupport.so from the filediff allowlist

libvendorsupport.so is included in soong system image. Remove it from
the allowlist.

Bug: 369678122
Test: lunch aosp_cf_x86_64_phone_soong_system-trunk_staging-userdebug
      && m
Change-Id: I222f98111299fe0cc79e4fb216e8d6e1993f88b2