Move clang warnings override out of libgui

These clang warnings overrides were introduced to mute warnings brought
in from bufferhub and its dependencies. A better way to handle this is
to mute those warnings in BufferHub headers and keep libgui free from
those overrides.

Bug: 72172820
Test: Build system
Change-Id: I7d8aa233ceeef353a7db2c43431ae64360c668b1